4x(x-2)-(5x-2)(2+5x)
Tìm x biết a) (x^2-4x+5)_(x^2-2x+1)=3 lớp 7
b)(4x^3-5X^2+3x-1)+(3-5x+5x^2-4x^3)=2
c)(3x-2)-(5x+4)=(x-3)-(X+5)
a, \(-4x+5+2x-1=3\Leftrightarrow-2x=-1\Leftrightarrow x=\dfrac{1}{2}\)
b, \(-2x+2=2\Leftrightarrow x=0\)
c, \(-2x-6=-8\Leftrightarrow x=1\)
Câu 1.Tính nhân 4x(x\(^2\)− 5x + 3).
A. 4x\(^3\)− 20x\(^2\) + 12x
B. 4x\(^3\)− 5x\(^2\)− 12x
C. 4x\(^2\)− 20x + 12
D. x\(^2\)− 5x + 12.
\(4x\left(x^2-5x+3\right)=4x^3-20x^2+12x\)
=> Chọn A
Tìm x, biết:
A) (x -1)^3+(2-x)(4+2x+x^2)+3x(x+2)=17
B) (x+2)(x^2-2x+4)-x(x^2-2)=15
C) (5x-2)(5x+2)-(5x+3)(5x-4)=8
D) (4x-3)(4x+2)+(4x+5)(1-4x)=2.5^2
a) (3x + 2)² + (4x + (4x - 1)² + (2 + 5x). (2-5x) y - 2 ) ² + 2(x+ x+y = z) (²-y) + (z - y)² Bat 3. Rut gọn các biểu thức sau a) (3x + 2)² + (4x + (4x - 1)² + (2 + 5x). (2-5x) y - 2 ) ² + 2(x+ x+y = z) (²-y) + (z - y)² Bài 4. Tính nhanh, 8.9² + dd² + 22.89. a) (3x + 2)² + (4x + (4x - 1)² + (2 + 5x). (2-5x) y - 2 ) ² + 2(x+ x+y = z) (²-y) + (z - y)² a) (3x + 2)² + (4x
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TÌM X biết:
a. (5x - 2)(5x + 2) - (5x + 3)(5x - 4) = 8
b. (4x - 3)( 4x + 2) + (4x + 5)(1 - 4x) =2.52
a) \(\left(5x-2\right)\left(5x+2\right)-\left(5x+3\right)\left(5x-4\right)=0\)
\(\Leftrightarrow5x+8=8\)
\(\Leftrightarrow5x=8-8\)
\(\Leftrightarrow x=5.0\)
\(\Leftrightarrow x=0\)
b)
\(\left(4x-3\right)\left(4x+2\right)+\left(4x+5\right)\left(1-4x\right)=2.5^2\)
\(16x^2+8x-12x-6+4x-16x^2+5-20x=50\)
\(-20x-1=50\)
\(-20x=51\)
\(x=\frac{-51}{20}\)
Vậy \(x=\frac{-51}{20}\)
Tính 4x(x + 5) − 9x\(^2\)
A.−5x\(^2\) + 20x
B. 5x\(^2\) + 7x
C. −5x\(^2\) + 5x
D. 4x\(^2\) − 29x
TÌM X biết:
a. (5x - 2)(5x + 2) - (5x + 3)(5x - 4) = 8
b. (4x - 3)( 4x + 2) + (4x + 5)(1 - 4x) =2.52
a ) \(\left(5x-2\right)\left(5x+2\right)-\left(5x+3\right)\left(5x-4\right)=8\)
\(\Leftrightarrow\left(5x\right)^2-4-\left(25x^2+15x-20x-12\right)=8\)
\(\Leftrightarrow25x^2-4-25x^2-15x+20x+12=8\)
\(\Leftrightarrow5x+8=8\)
\(\Leftrightarrow5x=0\)
\(\Leftrightarrow x=0\)
Vậy \(x=0\)
b ) \(\left(4x-3\right)\left(4x+2\right)+\left(4x+5\right)\left(1-4x\right)=2.5^2\)
\(\Leftrightarrow16x^2-12x+8x-6+4x+5-16x^2-20x=50\)
\(\Leftrightarrow-20x-1=50\)
\(\Leftrightarrow-20x=51\)
\(\Leftrightarrow x=-\dfrac{51}{20}\)
Vậy \(x=-\dfrac{51}{20}\)
Bài 1: Giải các phương trình: a)(5x^ 2 -45).( 4x-1 5 - 2x+1 3 )=0 b) (x^ 2 -2x+6).(2x-3)=4x^ 2 -9 d) 3 5x-1 + 2 3-5x = 4 (1-5x).(5x-3) c) (2x + 19)/(5x ^ 2 - 5) - 17/(x ^ 2 - 1) = 3/(1 - x) e) 3/(2x + 1) = 6/(2x + 3) + 8/(4x ^ 2 + 8x + 3) (x^ 2 -3x+2).(x^ 2 -9x+20)=40 (2x + 5)/95 + (2x + 6)/94 + (2x + 7)/93 = (2x + 93)/7 + (2x + 94)/6 + (2x + 95)/5 Bài 2: Giải các phương trình sau: g) a) (x + 2) ^ 2 + |5 - 2x| = x(x + 5) + 5 - 2x b) (x - 1) ^ 2 + |x + 21| - x ^ 2 - 13 = 0 d) |3x + 2| + |1 - 2x| = 5 - |x| c) |5 - 2x| = |1 - x| Bài 3: Cho biểu thức A = ((x + 2)/(x + 3) - 5/(x ^ 2 + x - 6) + 1/(2 - x)) / ((x ^ 2 - 5x + 4)/(x ^ 2 - 4)) a) Rút gọn A. b) Tim x de A = 3/2 c) Tìm giá trị nguyên c dot u a* d hat e A có giá trị nguyên. B = ((2x)/(2x ^ 2 - 5x + 3) - 5/(2x - 3)) / (3 + 2/(1 - x)) Bài 4: Cho biểu thức a) Rút gọn B. b) Tim* d tilde e B>0 . c) Tim* d hat e B= 1 6-x^ 2 . Bài 5: Cho biểu thức H = (2/(1 + 2x) + (4x ^ 2)/(4x ^ 2 - 1) - 1/(1 - 2x)) / (1/(2x - 1) - 1/(2x + 1)) a) Rút gọn H. b) Tìm giá trị nhỏ nhất của H. c)Tim* d vec e bi vec e u thic H= 3 2
Thực hiện phép tính :
a)5x2 - 3x . (x-2)
b) 3x.(x-5)-5x.(x+7)
c) 5x.(1/5x-2)=3.(6-1/3x2)
d) 7x.(x-5)+3.(x-2)
e) 5-4x.(x-2)+4x2
f)4x.(2x-3)-5x.(x-2)
\(a,5x^2-3x\left(x-2\right)\)
\(=5x^2-3x^2+6x\)
\(=2x^2+6x\)
\(b,3x\left(x-5\right)-5x\left(x+7\right)\)
\(=3x^2-15x-5x^2-35x\)
\(=-2x^2-50x\)
c, Đề ko rõ Yang Yang
\(d,7x\left(x-5\right)+3\left(x-2\right)\)
\(=7x^2-35x+3x-6\)
\(=7x^2-32x-6\)
\(e,5-4x\left(x-2\right)+4x^2\)
\(=5-4x^2+8x+4x^2\)
\(=5+8x\)
\(f,4x\left(2x-3\right)-5x\left(x-2\right)\)
\(=8x^2-12x-5x^2+10x\)
\(=3x^2-2x\)
giải các phương trình sau:
\(\sqrt{x^2+6x+9}=3x-6\)
\(\sqrt{x^2-2x+1}=\sqrt{4x^2-4x+1}\)
\(\sqrt{4-5x}=2-5x\)
\(\sqrt{4-5x}=\sqrt{2-5x}\)
\(a,PT\Leftrightarrow\left|x+3\right|=3x-6\\ \Leftrightarrow\left[{}\begin{matrix}x+3=3x-6\left(x\ge-3\right)\\x+3=6-3x\left(x< -3\right)\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=\dfrac{9}{2}\left(tm\right)\\x=\dfrac{3}{4}\left(ktm\right)\end{matrix}\right.\\ \Leftrightarrow x=\dfrac{9}{2}\\ b,PT\Leftrightarrow\left|x-1\right|=\left|2x-1\right|\\ \Leftrightarrow\left[{}\begin{matrix}x-1=2x-1\\1-x=2x-1\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=\dfrac{2}{3}\end{matrix}\right.\)
\(c,ĐK:x\le\dfrac{2}{5}\\ PT\Leftrightarrow4-5x=25x^2-20x+4\\ \Leftrightarrow25x^2-15x=0\\ \Leftrightarrow5x\left(5x-3\right)=0\\ \Leftrightarrow\left[{}\begin{matrix}x=0\left(tm\right)\\x=\dfrac{3}{5}\left(ktm\right)\end{matrix}\right.\Leftrightarrow x=0\\ d,ĐK:x\le\dfrac{2}{5}\\ PT\Leftrightarrow4-5x=2-5x\\ \Leftrightarrow x\in\varnothing\)