1)tìm x biết:
a)(x-2)^2=1
b)(2x-1)^3=-8
c)(x+1/2)^2=1/16
d)(x-2)^3=-27
e(2x-3)^2=25
g)3^x-1=1/243
h)2^x+2^x+3=144
k)81^-2x*27^x=95
tìm x biết:
a) (x-3)2-4=0
b) x2-2x=24
c) (x+4)2-(x+1)(x-1)=16
d) (2x+1)2-4(x-1)2=9
e) (x+3)2-(x-4)(x+8)=1
f) (2x-1)2+(x+3)2-5(x+7)(x-7)=0
g) 3(x+2)2+(2x-1)2-7(x+3)(x-3)=36
- Gửi lẻ câu hỏi ra nha bạn 2 3 câu 1 lần thôi .
a) (x-3)2-4=0
⇒ (x-3)2=4
⇒ hoặc x-3=2⇒x=5
hoặc x-3=-2⇒x=1
c) (x+4)2-(x+1)(x-1)=16
⇒ x2+8x+16-x2+1=16
⇒ 8x+17=16
⇒ 8x=-1
⇒ x=-1/8
1)tìm x biết:
a)(x-2)^2=1
b)(2x-1)^3=-8
c)(x+1/2)^2=1/16
d)(x-2)^3=-27
e(2x-3)^2=25
g)3^x-1=1/243
h)2^x+2^x+3=144
k)81^-2x*27^x=95
a) (X - 2)\(^2\) = 1 <=> X - 2 = \(\sqrt{1}\) <=> X = 1 + 2 <=> X = 3
Bài 8. Tìm x ϵ N biết:
a) x3=27
b) (2x-1)3=8
c) (x-2)2=16
d) (2x – 3)2=9
e) 2x+5=34:32
f) (3x-24).73=2.74
Bài 8. Tìm x ϵ N biết:
a) x3=27
b) (2x-1)3=8
c) (x-2)2=16
d) (2x – 3)2=9
e) 2x+5=34:32
f) (3x-24).73=2.74
Bài 4. Tìm số nguyên x , biết:
a) |x - 2|= 0 b) |x + 3|= 1 c) -3 |4 - x|= -9 d) |2x + 1|= -2
Bài 5. Tìm số nguyên x, biết:
a) (x + 3)mũ 2 = 36 b) (x + 5)mũ 2 =100 c) (2x - 4)mũ 2 = 0 d) (x - 1)mũ 3 = 27
tìm x biết:
a) x - 3= (3 - x)^2
b) x^3 + 3/2x^2 + 3/4x + 1/8 = 1/64
c) 8x^3 - 50x = 0
d) (x - 2) (x^2 + 2x + 7) + 2(x^2 - 4) - 5(x - 2) = 0
e) x(x + 3) - x^2 - 3x = 0
f) x^3 + 27 + (x + 3) (x - 9) = 0
Giúp mik vs ạ
a) Ta có: \(\left(x-3\right)=\left(3-x\right)^2\)
\(\Leftrightarrow\left(x-3\right)^2-\left(x-3\right)=0\)
\(\Leftrightarrow\left(x-3\right)\left(x-4\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=3\\x=4\end{matrix}\right.\)
b) Ta có: \(x^3+\dfrac{3}{2}x^2+\dfrac{3}{4}x+\dfrac{1}{8}=\dfrac{1}{64}\)
\(\Leftrightarrow x^3+3\cdot x^2\cdot\dfrac{1}{2}+3\cdot x\cdot\dfrac{1}{4}+\left(\dfrac{1}{2}\right)^3=\dfrac{1}{64}\)
\(\Leftrightarrow\left(x+\dfrac{1}{2}\right)^3=\left(\dfrac{1}{4}\right)^3\)
\(\Leftrightarrow x+\dfrac{1}{2}=\dfrac{1}{4}\)
hay \(x=-\dfrac{1}{4}\)
c) Ta có: \(8x^3-50x=0\)
\(\Leftrightarrow2x\left(4x^2-25\right)=0\)
\(\Leftrightarrow x\left(2x-5\right)\left(2x+5\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{5}{2}\\x=-\dfrac{5}{2}\end{matrix}\right.\)
e) Ta có: \(x\left(x+3\right)-x^2-3x=0\)
\(\Leftrightarrow\left(x+3\right)\left(x-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-3\\x=1\end{matrix}\right.\)
f) Ta có: \(x^3+27+\left(x+3\right)\left(x-9\right)=0\)
\(\Leftrightarrow\left(x+3\right)\left(x^2-3x+9\right)+\left(x+3\right)\left(x-9\right)=0\)
\(\Leftrightarrow\left(x+3\right)\left(x^2-2x\right)=0\)
\(\Leftrightarrow x\left(x-2\right)\left(x+3\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=0\\x=2\\x=-3\end{matrix}\right.\)
Tìm x biết:
a)3.(x-2)+2.(x-3)=5
b)(2x-8)2-16=0
c)(2x-1)2-(4x+1).(x-3)=3
a) \(3\left(x-2\right)+2\left(x-3\right)=5\)
\(\Rightarrow3x-6+2x-6=5\)
\(\Rightarrow5x=17\Rightarrow x=\dfrac{17}{5}\)
b) \(\left(2x-8\right)^2-16=0\)
\(\Rightarrow\left(2x-8-4\right)\left(2x-8+4\right)=0\)
\(\Rightarrow\left(2x-12\right)\left(2x-4\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}2x=12\\2x=4\end{matrix}\right.\)\(\Rightarrow\left[{}\begin{matrix}x=6\\x=2\end{matrix}\right.\)
c) \(\left(2x-1\right)^2-\left(4x+1\right)\left(x-3\right)=3\)
\(\Rightarrow4x^2-4x+1-4x^2+12x-x+3=3\)
\(\Rightarrow7x=-1\Rightarrow x=-\dfrac{1}{7}\)
a: Ta có: \(3\left(x-2\right)+2\left(x-3\right)=5\)
\(\Leftrightarrow3x-6+2x-6=5\)
\(\Leftrightarrow5x=17\)
hay \(x=\dfrac{17}{5}\)
b: Ta có: \(\left(2x-8\right)^2-16=0\)
\(\Leftrightarrow\left(2x-4\right)\left(2x-12\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x=2\\x=6\end{matrix}\right.\)
a. \(3\left(x-2\right)+2\left(x-3\right)=5\)
\(\Leftrightarrow3x-6+2x-6=5\)
\(\Leftrightarrow5x=17\)
\(\Leftrightarrow x=\dfrac{17}{5}\)
b. \(\left(2x-8\right)^2-16=0\)
\(\Leftrightarrow\left(2x-8-4\right)\left(2x-8+4\right)=0\)
\(\Leftrightarrow4\left(x-6\right)\left(x-2\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}x-6=0\\x-2=0\end{matrix}\right.\) \(\Leftrightarrow\left[{}\begin{matrix}x=6\\x=2\end{matrix}\right.\)
c. \(\left(2x-1\right)^2-\left(4x+1\right)\left(x-3\right)=3\)
\(\Leftrightarrow4x^2-4x+1-4x^2+11x+3-3=0\)
\(\Leftrightarrow7x+1=0\)
\(\Leftrightarrow x=-\dfrac{1}{7}\)
Rút gọn biểu thức:
a) (x + 2)(x – 2) – (x + 1)2
b) (2x – 1)(4x2 + 2x + 1) – (2x + 1)( 4x2 – 2x + 1)
3. Tìm x biết:
a) (x + 2)(x2 – 2x + 4) – x(x2 – 2) = 15
b) (x – 1)3 – x(x2 – 3x – 4) = 13
thanks
\(a,=x^2-4-x^2-2x-1=-2x-5\\ b,=8x^3-1-8x^3-1=-2\\ 3,\\ a,\Rightarrow x^3+8-x^3+2x=15\\ \Rightarrow2x=7\Rightarrow x=\dfrac{7}{2}\\ b,\Rightarrow x^3-3x^2+3x-1-x^3+3x^2+4x=13\\ \Rightarrow7x=14\Rightarrow x=2\)
Bài 2:
a) \(=x^2-4-x^2-2x-1=-2x-5\)
b) \(=8x^3-1-8x^3-1=-2\)
Bài 3:
a) \(\Rightarrow x^3+8-x^3+2x=15\)
\(\Rightarrow2x=7\Rightarrow x=\dfrac{7}{2}\)
b) \(\Rightarrow x^3-3x^2+3x-1-x^3+3x^2+4x=13\)
\(\Rightarrow7x=14\Rightarrow x=2\)
Tìm x, biết:
a) (2x + 1)^2 - 4(x + 2)^2 = 9
b) (x + 3)^2 - (x - 4)( x + 8) = 1
c) 3(x + 2)^2 + (2x - 1)^2 - 7(x + 3)(x - 3) = 36
d)(x - 3)(x^2 + 3x + 9) + x(x + 2)(2 - x) = 1
a) \(\left(2x+1\right)^2-4\left(x+2\right)^2=9\\ \Rightarrow\left[2x+1-2\left(x+2\right)\right]\left[2x+1+2\left(x+2\right)\right]=9\\ \Rightarrow\left(2x+1-2x-4\right)\left(2x+1+2x+4\right)=9\\ \Rightarrow-3\left(4x+5\right)=9\\ \Rightarrow4x+5=-3\\ \Rightarrow4x=-8\\ \Rightarrow x=-2\)
\(b) (x+3)^2-(x-4)(x+8)=1 <=>x^2+6x=9-(x^2+8x-4x-32)=0 \)
\(.<=> X^2+6x+9-x^2-8x+4x+32-1=0\)
\(<=>2x=-40<=>x=-20\)
=> ptrình có tập nghiêm S={-20}
c) 3(x + 2)^2 + (2x - 1)^2 - 7(x + 3)(x - 3) = 36
\(<=>3(x^2+4x+4)+(4x^2-4x+1)-7(x^2-9)=36\)
\(<=>3x^2+12x+12+4x^2-4x+1-7x^2+49=0\)
\(<=>8x=-62<=>x=7,75\)
=> ptrình có tập nghiệm S={7,75}
d)d)(x - 3)(x^2 + 3x + 9) + x(x + 2)(2 - x) = 1
\(<=> x^3+3x^2+9x-3x^2-9x-27-x(x^2-4)=1\)
\(<=>x^3+3x^2+9x-3x^2-9x-27-x^3+4x-1=0\)
\(<=> 4x=28<=> x=7\)
=> ptrình có tập nghiệm S={7}