tìm x thuộc Q biết: \(\left(2.x+3\right)^2=16\)
tìm x thuộc Q, biết rằng :
a) \(\left(x-\frac{1}{2}\right)^2=0\)
b)\(\left(x-2\right)^2=1\)
c) \(\left(2x-1\right)^3=-8\)
d) \(\left(x+\frac{1}{2}\right)^2=\frac{1}{16}\)
a) \(\left(x-\frac{1}{2}\right)^2=0\)
\(x-\frac{1}{2}=0\)
\(x=0+\frac{1}{2}\)
\(x=\frac{1}{2}\)
b) \(\left(x-2\right)^2=1\)
\(\left(x-2\right)^2=1^2\)
\(x-2=1\)
\(x=1+2\)
\(x=3\)
c) \(\left(2x-1\right)^3=\left(-8\right)\)
\(\left(2x-1\right)^3=\left(-2\right)^3\)
\(2x-1=\left(-2\right)\)
\(2x=\left(-2\right)+1\)
\(2x=-1\)
\(x=-\frac{1}{2}\)
d) \(\left(x+\frac{1}{2}\right)^2=\frac{1}{16}\)
\(\left(x+\frac{1}{2}\right)^2=\left(\frac{1}{4}\right)^2\)
\(x+\frac{1}{2}=\frac{1}{4}\)
\(x=\frac{1}{4}-\frac{1}{2}\)
\(x=-\frac{1}{4}\)
a) \(\left(x-\frac{1}{2}\right)^2=0\)
\(\Leftrightarrow x-\frac{1}{2}=0\)
\(\Leftrightarrow x=\frac{1}{2}\)
b) \(\left(x-2\right)^2=1\)
\(\Leftrightarrow\orbr{\begin{cases}x-2=1\\x-2=-1\end{cases}\Leftrightarrow\orbr{\begin{cases}x=3\\x=1\end{cases}}}\)
c) \(\left(2x-1\right)^2=-8\)
\(\Leftrightarrow2x-1=-2\)
\(\Leftrightarrow2x=-1\)
\(\Leftrightarrow x=-\frac{1}{2}\)
d) \(\left(x+\frac{1}{2}\right)^2=\frac{1}{16}\)
\(\Rightarrow\orbr{\begin{cases}x+\frac{1}{2}=\frac{1}{4}\\x+\frac{1}{2}=-\frac{1}{4}\end{cases}\Rightarrow\orbr{\begin{cases}x=-\frac{1}{4}\\x=-\frac{3}{4}\end{cases}}}\)
Tìm x thuộc Q, biết rằng:
a) \(\left(x-\frac{1}{2}\right)^2=0\)
b) \(\left(x-2\right)^2=1\)
c) \(\left(2x-1\right)^3=-8\)
d) \(\left(x+\frac{1}{2}\right)^2=\frac{1}{16}\)
a) \(\left(x-\frac{1}{2}\right)^2=0\)
\(\Rightarrow\orbr{\begin{cases}x=\frac{-1}{2}\\x=\frac{1}{2}\end{cases}}\)
b) \(\left(x-2\right)^2=1\)
\(\Leftrightarrow\left(x-2\right)^2-1=0\)
\(\Leftrightarrow\left(x-2-1\right)\left(x-2+1\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(x-1\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}x-3=0\\x-1=0\end{cases}\Leftrightarrow\orbr{\begin{cases}x=3\\x=1\end{cases}}}\)
c) \(\left(2x-1\right)^3=-8\)
\(\Leftrightarrow2x-1=-2\)
\(\Leftrightarrow2x=-1\)
\(\Leftrightarrow x=\frac{-1}{2}\)
d) \(\left(x+\frac{1}{2}\right)^2=\frac{1}{16}\)
\(\Rightarrow x+\frac{1}{2}=\frac{1}{4}\)
\(\Rightarrow x=-\frac{1}{4}\)
a>(x-1/2)^2=0
(x-1/2)^2=0^2
=>x-1/2=0
x=1/2
b>(x-2)^2=1
(x-2)^2=1^2
=>x-2=1
x=3
(2x-1)^3=-8
=>(2x-1)^3=-2^3
=>2x-1=-2
2x=-1
x=-0,5
d>(x+1/2)^2=1/16
(x+1/2)^2=(1/4)^2
=>x+1/2=1/4
x=1/4-1/2
x=-1/4
chuc ban may man trong cuoc song!!!!!
Tìm x,y thuộc Z biết:
a, \(\left(x+1\right)^2+\left(y+5\right)^2=16\)
b, \(\left(x+4\right)^2+\left(y-2\right)^4=5\)
c, \(|x-3|+\left(y-7\right)^2=3\)
d, \(\left(x-7\right)^4+\left(y-2\right)^2=20\)
Giải nhanh dùm mình nhé!!
a, [x+1]2 + [y+5]2 = 16
Theo đề, ta có: 0 \(\le\)[x+1]2 \(\le\)16; 0\(\le\)[y+5]2 \(\le\)16
Dễ dàng nhận thấy [x+1]2 và [y+5]2 là hai số chính phương, mà từ 0 - 16 chỉ có hai số chính phương 0 và 16 là có tổng là 16
=> Có hai trường hợp:
* \(\hept{\begin{cases}\left[x+1\right]^2=0\\\left[y+5\right]^2=16\end{cases}\Rightarrow}\hept{\begin{cases}x+1=0\\\hept{\begin{cases}y+5=4\\y+5=-4\end{cases}}\end{cases}\Rightarrow\hept{\begin{cases}x=-1\\y=-1\end{cases};}\hept{\begin{cases}x=-1\\y=-9\sqrt[]{}\sqrt[]{}\end{cases}}}\)
Bài 1 :
a) \(16.\left(38-2\right)-38\left(16-1\right)\)
b) \(\left(-41\right).\left(59+2\right)+59\left(41-2\right)\)
Bài 2 :
Tìm các số x ; y ; x biết rằng :
\(\)x + y = 2 ; y + z = 3 ; z + x = -5
Bài 3 : Tìm x ; y \(\in\) Z biết rằng :
( y + 1 ) . xy - 1 ) = 3
Bài 1 : Tính nhanh
a) 16.(38−2)−38(16−1)16.(38−2)−38(16−1)
b) (−41).(59+2)+59(41−2)(−41).(59+2)+59(41−2)
Bài 2 :
Tìm các số x ; y ; x biết rằng :
x + y = 2 ; y + z = 3 ; z + x = -5
Bài 3 : Tìm x ; y ∈∈ Z biết rằng :
( y + 1 ) . xy - 1 ) = 3
a) 16.(38−2)−38(16−1)
= 16.38 - 16.2 - 38.16 - 38.1
=-16.2 - 38.1
=-32-38
=-70
tìm x biết:
a, \(\left(x+4\right)^2-\left(x+1\right)\left(x-1\right)=16\)
b, \(\left(2x-1\right)^2-\left(x+3\right)^2-5\left(x+7\right)\left(x-7\right)=0\)
a,\((x+4)^2-(x+1)(x-1)=16\)
\(\Rightarrow x^2+8x+16-x^2+1=16\)
\(\Rightarrow 8x=-1\Rightarrow x=-\dfrac{1}{8}\)
b,\((2x-1)^2-(x+3)^2-5(x+7)(x-7)=0\)
\(\Rightarrow 4x^2-4x+1-(x^2+6x+9)-5(x^2-49)=0\)
\(\Rightarrow 4x^2-4x+1-x^2-6x-9-5x^2-245=0\)
\(\Rightarrow -x^2-10x-244=0\)
\(\Rightarrow -(x^2-10x+25)-219=0\)
\(\Rightarrow -(x-5)^2-219=0\)
\(\Rightarrow (x-5)^2+219=0\)
Mà \((x-5)^2+219>0\) suy ra PT vô nghiệm
Tìm x biết :
\(\left(x+2\right)^3-\left(x-2\right)^3-16=108\)
\(< =>\left(\left(x+2\right)^3-\left(x-2\right)^3\right)-16-108=0\)
\(< =>\left(x+2-x+2\right)\left(\left(x+2\right)^2+\left(x+2\right)\left(x-2\right)+\left(x-2\right)^2\right)-16-108=0\)
\(< =>4\left(x^2+4x+4+x^2-4+x^2-4x+4\right)-16-108=0\)
\(< =>4\left(3x^2+4\right)-16-108=0\)
\(< =>12x^2+16-16-108=0\)
\(< =>12x^2-108=0\)
\(< =>12\left(x^2-9\right)=0\)
\(< =>x^2-9=0\)
\(
< =>\left(x-3\right)\left(x+3\right)=0\)
\(< =>\orbr{\begin{cases}x-3=0\\x+3=0\end{cases}< =>\orbr{\begin{cases}x=3\\x=-3\end{cases}}}\)
(x+2)3-(x-2)3-16=108
x3+3x2.2+3.x.22+23-x3+3x2.2-3.x.22+23=124
(x3-x3)+(6x2+6x2)+(12x-12x)+(8+8)=124
12x2+16=124
12x2=108
x2=9
x=-3 hoặc x=3
x3 +6x2 + 12x + 8 - x3 +6x2 - 12x +8 -16 = 108
12x2 = 108
x2 = 9
x = +- 3
Tìm x biết :
\(a)\)\(\left|5\left(2x+3\right)\right|+\left|2\left(2x+3\right)\right|+\left|2x+3\right|=16\)
\(b)\)\(\left|x^2+\left|6x-2\right|\right|=x^2+4\)
tìm x,y thuộc N biết
\(\left(2^x+1\right)\left(2^x+2\right)\left(2^x+3\right)\left(2^x+4\right)-5^y=11879\)
Tìm x, biết:
a, \(25x^2-9=0\)
\(b,\left(x+4\right)^2-\left(x+1\right)\left(x-1\right)=16\)
\(c,\left(2x-1\right)^2+\left(x+3\right)^2-5\left(x+7\right)\left(x-7\right)=0\)
a) \(25x^2-9=0\)
\(\Leftrightarrow\left(5x\right)^2-3^2=0\)
\(\Leftrightarrow\left(5x+3\right)\left(5x-3\right)=0\)
\(\Leftrightarrow\orbr{\begin{cases}5x-3=0\\5x+3=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{3}{5}\\x=-\frac{3}{5}\end{cases}}\)
Vậy \(S=\left\{\frac{3}{5};\frac{-3}{5}\right\}\)
b) \(\left(x+4\right)^2-\left(x+1\right)\left(x-1\right)=16\)
\(\Leftrightarrow\left(x^2+8x+16\right)-\left(x^2-1\right)=16\)
\(\Leftrightarrow x^2+8x+16-x^2+1=16\)
\(\Leftrightarrow8x+17=16\)
\(\Leftrightarrow8x=-1\)
\(\Leftrightarrow x=-\frac{1}{8}\)
Vậy.........
c)\(\left(2x-1\right)^2+\left(x+3\right)^2-5\left(x+7\right)\left(x-7\right)=0\)
\(\Leftrightarrow\left(4x^2-4x+1\right)+\left(x^2+6x+9\right)-5\left(x^2-49\right)=0\)
\(\Leftrightarrow4x^2-4x+1+x^2+6x+9-5x^2+245=0\)
\(\Leftrightarrow2x=-255\)
\(\Leftrightarrow x=-127,5\)
Vậy.............
có j sai xót mong m.n bỏ qua☺
a) \(25x^2-9=0\)
<=> \(\left(5x\right)^2=9\)
<=> \(\left(5x\right)^2=3^2\)
<=> \(5x=3\)
<=> \(x=\frac{3}{5}\)
b) \(\left(x+4\right)^2-\left(x-1\right)\left(x+1\right)=16\)
<=> \(x^2+2.x.4+4^2-\left(x^2-1^2\right)=16\)
<=> \(x^2+8x+16-x^2+1=16\)
<=> \(\left(x^2-x^2\right)+8x+\left(16+1\right)=16\)
<=> \(8x+17=16\)
<=> \(8x=-1\)
<=> \(x=\frac{-1}{8}\)
c) \(\left(2x-1\right)^2+\left(x+3\right)^2-5\left(x+7\right)\left(x-7\right)=0\)
<=> \(\left(2x\right)^2-2.2x.1+1^2+x^2+2.x.3+3^2-5\left(x^2-7^2\right)=0\)
<=> \(4x^2-4x+1+x^2+6x+9-5x^2+5.7^2=0\)
<=> \(\left(4x^2+x^2-5x^2\right)-\left(4x-6x\right)+\left(1+9+5.7^2\right)=0\)
<=> \(2x+245=0\)
<=> \(2x=-245\)
<=> \(x=\frac{-245}{2}\)
a) \(25x^2-9=0\)
\(\Rightarrow25x^2-3^2=0\)
\(\Rightarrow\left(25x+3\right).\left(25x-3\right)=0\)
\(\Rightarrow\orbr{\begin{cases}25x+3=0\\25x-3=0\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}25x=-3\\25x=3\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=\frac{-3}{25}\\x=\frac{3}{25}\end{cases}}\)
b) \(\left(x+4\right)^2-\left(x+1\right)\left(x-1\right)=16\)
\(\Rightarrow\left(x+4\right)^2-\left[\left(x+1\right)^2-\left(x-1\right)^2\right]=16\)
\(\Rightarrow\left(x+4\right)^2=16\)
\(\Rightarrow\left(x+4\right)^2=4^2\)
\(\Rightarrow x+4=4\)
\(\Rightarrow x=0\)
c) \(\left(2x-1\right)^2+\left(x+3\right)^2-5\left(x+7\right)\left(x-7\right)=0\)
\(\Rightarrow\left(2x-1\right)+2\left(2x-1\right)\left(x+3\right)+\left(x+3\right)^2-5.\left(x+7\right)^2-\left(x-7\right)^2=0\)
\(\Rightarrow2\left(x+3\right)^3=0\)
\(\Rightarrow\left(x+3\right)^2=0\)
\(\Rightarrow x=3\)