\(7-5x>2\\ \Leftrightarrow-5x>-\left(7-2\right)\\ \Leftrightarrow-5x>-5\\ \Leftrightarrow x< -\dfrac{5}{-5}\\ \Leftrightarrow x< 1\)
\(7-5x>2\\ \Leftrightarrow-5x>-\left(7-2\right)\\ \Leftrightarrow-5x>-5\\ \Leftrightarrow x< -\dfrac{5}{-5}\\ \Leftrightarrow x< 1\)
Bài 1: Rút gọn
A=(7-2x)(7+2x)+(2x+7)2
B=(4x-5)2-(2x-1)(8x-5)
C=(5x-3)2-2(5x-3)(5-5x)+(5x-5)2
D=(2a+3b-c)(2a-3b+c)-(4a2-9b2-c2)
Bài 1: Rút gọn
A=(7-2x)(7+2x)+(2x+7)2
B=(4x-5)2-(2x-1)(8x-5)
C=(5x-3)2-2(5x-3)(5-5x)+(5x-5)2
D=(2a+3b-c)(2a-3b+c)-(4a2-9b2-c2)
Tìm x:
a ) (3x -5)^2 - (3x +2) (3x - 2) = 8
b ) (5x + 3) (3 - 5x) + (5x - 7) ( 5x - 7) = 1
Tìm x, biết
a/ 6x^2 -(2x+3)(3x-2)=7
b/5x(12+7)-3x(80x-5)=-100
c/(3x-5)(7-5x)-(5x-2)(2-3x)=4
thu gọn
a)(2x-7)^2+(2x+7)^2-2(2x+7)(2x-7)
b)(5x-3)^2-(5x+3)^2-15(2x-1)
(x^2-5x+9)^2 + 4(x^2-3x+7)^2 = 4(x^2-5x+9)(x^2-3x+7)
Tìm x biết
(5x-1)2-(5x-4)(5x+4)=7
căn (3x^2+5x+1) - căn (3x^2+5x-7) = 2
Tim x
6x^2-(2x+5)(3x-2)=7
(3x-5)*(7-5x)-(5x+2)(2-3x)=4