Rút gọn các biểu thức sau:a, 5 ( 2x - 1 )2 +4 ( x - 1) ( x + 3) -2 ( 5- 3x)2 b, ( 9x - 1)2 + (1 - 5x)2 + 2 ( 9x - 1) ( 1 - 5x )c, (x2 - 5x + 1)2 + 2( 5x - 1) ( x2 - 5x + 1) + ( 5x - 1)2d, ( x2 + 3x + 1)2 + ( 3x - 1)2 - 2( x2 + 3x + 1) ( 3x - 1)e, ( x + y )3 - ( x - y)3f, ( x - y - 1)3 - ( x - y + 1)3 + 6 ( x -...
Đọc tiếp
Rút gọn các biểu thức sau:
a, 5 ( 2x - 1 )2 +4 ( x - 1) ( x + 3) -2 ( 5- 3x)2
b, ( 9x - 1)2 + (1 - 5x)2 + 2 ( 9x - 1) ( 1 - 5x )
c, (x2 - 5x + 1)2 + 2( 5x - 1) ( x2 - 5x + 1) + ( 5x - 1)2
d, ( x2 + 3x + 1)2 + ( 3x - 1)2 - 2( x2 + 3x + 1) ( 3x - 1)
e, ( x + y )3 - ( x - y)3
f, ( x - y - 1)3 - ( x - y + 1)3 + 6 ( x - y)2
a, \(5\left(2x-1\right)^2+4\left(x-1\right)\left(x+3\right)-2\left(5-3x\right)^2\)
\(=20x^2-20x+5+4x^2+12x-4x-12-50+60x-18x^2\)
\(=6x^2+48x-57\)
b, \(\left(9x-1\right)^2+\left(1-5x\right)^2+2\left(9x-1\right)\left(1-5x\right)\)
\(=81x^2-18x+1+1-10x+25x^2+18x-90x^2-2+10x\)
\(=16x^2\)
c;d;e;f tự làm, đầu I giữ lấy còn trường tồn:)
\(5\left(2x-1\right)^2+4\left(x-1\right)\left(x+3\right)-2\left(5-3x\right)^2\)
\(=5\left(4x^2-4x+1\right)+4\left(x^2+2x-3\right)-2\left(25-30x+9x^2\right)\)
\(=20x^2-20x+5+4x^2+8x-12-50+60x-18x^2\)
\(=\left(20x^2+4x^2-18x^2\right)+\left(60x+8x-20x\right)+\left(5-12-50\right)\)
\(=6x^2+48x-57\)