X + 2X = -36
(2x-1).(4x2+2x+1)-(3+2x).(3+2x).(3+2x)+36.(x-1).(x-1)
tìm x biết (2x+5).(2x-7)-(2x-3)^2=36
`(2x+5)(2x-7)-(2x-3)^2=36`
`<=>4x^2-14x+10x-35-(4x^2-12x+9)=36`
`<=>4x^2-4x-35-4x^2+12x-9=36`
`<=>8x-44=36`
`<=>8x=80`
`<=>x=10`
Vậy `S={10}`
Ta có: \(\left(2x+5\right)\left(2x-7\right)-\left(2x-3\right)^2=36\)
\(\Leftrightarrow4x^2-14x+10x-35-\left(4x^2-12x+9\right)=36\)
\(\Leftrightarrow4x^2-4x-35-4x^2+12x-9=36\)
\(\Leftrightarrow8x-44=36\)
\(\Leftrightarrow8x=80\)
hay x=10
Vậy: S={10}
Tìm x a, (4x-15)-(2x-3)=36 b, 2x-4=x+5
a: =>4x-15-2x+3=36
=>2x-12=36
=>2x=48
hay x=24
b: =>2x-x=5+4
hay x=9
Tìm x biết
a.(2x-3)^2=36
b.(2x-3)^2=36
a. (2x-3)2 = 36
(2x-3)2 = 62
=> TH1: 2x - 3 = 6
2x = 9
x = 9/2
TH2: 2x - 3 = -6
2x = -6 + 3
2x = -3
x = -3/2
Vậy x \(\in\){ -3/2 ; 9/2)
Câu b tương tự
a.(2x-3)^2=36
\(\Rightarrow\left(2x-3\right)^2=6^2\)
\(\Rightarrow2x-3=6\)
\(\Rightarrow2x=9\)\(\Rightarrow x=9:2=\frac{9}{2}\)
a)\(\left(2x-3\right)^2=36\)
\(\Rightarrow\left(2x-3\right)^2=6^2\)
\(\Rightarrow\hept{\begin{cases}2x-3=6\\2x-3=-6\end{cases}\Leftrightarrow\hept{\begin{cases}x=\frac{9}{2}\\x=-\frac{3}{2}\end{cases}}}\)
b)
ĐKXĐ: \(x\ne-\dfrac{3}{2}\)
Để A đạt giá trị nguyên thì \(-2x^2+x+36⋮2x+3\)
\(\Leftrightarrow-2x^2-3x+4x+6+30⋮2x+3\)
\(\Leftrightarrow-x\left(2x+3\right)+2\left(2x+3\right)+30⋮2x+3\)
\(\Leftrightarrow\left(2x+3\right)\left(-x+2\right)+30⋮2x+3\)
mà \(\left(2x+3\right)\left(-x+2\right)⋮2x+3\)
nên \(30⋮2x+3\)
\(\Leftrightarrow2x+3\inƯ\left(30\right)\)
\(\Leftrightarrow2x+3\in\left\{1;-1;2;-2;3;-3;5;-5;6;-6;10;-10;15;-15;30;-30\right\}\)
\(\Leftrightarrow2x\in\left\{-2;-4;1;-5;0;-6;2;-8;3;-9;7;-13;12;-18;27;-33\right\}\)
hay \(x\in\left\{-1;-2;\dfrac{1}{2};\dfrac{-5}{2};0;-3;1;-4;\dfrac{3}{2};\dfrac{-9}{2};\dfrac{7}{2};\dfrac{-13}{2};6;-9;\dfrac{27}{2};\dfrac{-33}{2}\right\}\)(thỏa ĐK)
Vậy: \(x\in\left\{-1;-2;\dfrac{1}{2};\dfrac{-5}{2};0;-3;1;-4;\dfrac{3}{2};\dfrac{-9}{2};\dfrac{7}{2};\dfrac{-13}{2};6;-9;\dfrac{27}{2};\dfrac{-33}{2}\right\}\)
(2x+1)^3=125
(2x-1)^4=16
6.3^x-2.3^x=36
2^x+1-2^x=32
\(\left(2x+1\right)^3=125\\ \Rightarrow\left(2x+1\right)^3=5^3\\ \Rightarrow2x+1=5\\ \Rightarrow2x=4\\ \Rightarrow x=2.\\ b,\left(2x-1\right)^4=16\\ \Rightarrow\left(2x-1\right)^4=2^4\\ \Rightarrow2x-1=2\\ \Rightarrow2x=3\\ \Rightarrow x=\dfrac{3}{2}.\\ c,6.3^x-2.3^x=36\\ \Rightarrow3^x.\left(6-2\right)=36\\ \Rightarrow3^x.4=36\\ \Rightarrow3^x=9\\ \Rightarrow3^x=3^2\\ \Rightarrow x=2.\\ d,2^{x+1}-2^x=32\\ \Rightarrow2^x.\left(2-1\right)=32\\ \Rightarrow2^x=2^5\\ \Rightarrow x=5.\)
(x + 2)^2 + (2x -1)^2-(x - 3)^2 = 36
(2x -1)2 + (x + 3)2 - 5(x + 7)(x - 7) = 0
a: Ta có: \(\left(x+2\right)^2+\left(2x-1\right)^2-\left(x-3\right)^2=36\)
\(\Leftrightarrow x^2+4x+4+4x^2-4x+1-x^2+6x-9=36\)
\(\Leftrightarrow4x^2+6x-4-36=0\)
\(\Leftrightarrow4x^2+6x-40=0\)
\(\text{Δ}=6^2-4\cdot4\cdot\left(-40\right)=676\)
Vì Δ>0 nên phương trình có hai nghiệm phân biệt là:
\(\left\{{}\begin{matrix}x_1=\dfrac{-6-26}{8}=-4\\x_2=\dfrac{-6+26}{8}=\dfrac{5}{2}\end{matrix}\right.\)
(x^3-2x^2-15x+36):(x+4)
\(=\left(x^3+4x^2-6x^2-24x+9x+36\right):\left(x+4\right)\\ =\left[x^2\left(x+4\right)-6x\left(x+4\right)+9\left(x+4\right)\right]:\left(x+4\right)\\ =x^2-6x+9\)
2x - 2/3 + 1/2x = -1
31/36 - (1/3 - x)2 = 5/6
`2x -2/3 +1/2x =-1`
`=> 2x+1/2x =-1+2/3`
`=> (2+1/2) x =-3/3 + 2/3`
`= 5/2 x = -1/3`
`=> x=-1/3 : 5/2`
`=>x= -2/15`
`31/36 - (1/3-x)^2 =5/6`
`=> (1/3-x)^2 = 31/36 - 5/6`
`=> (1/3-x)^2 =1/36`
`=> (1/3-x)^2 = (+-1/6)^2`
\(\Rightarrow\left[{}\begin{matrix}\dfrac{1}{3}-x=\dfrac{1}{6}\\\dfrac{1}{3}-x=-\dfrac{1}{6}\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=\dfrac{1}{6}\\x=\dfrac{1}{2}\end{matrix}\right.\)