Question

Answer 1

a: Ta có: \(\left(5x-1\right)\left(x+3\right)-\left(x-2\right)\left(5x-4\right)\)

\(=5x^2+15x-x-3-5x^2+4x+10x-8\)

\(=28x-11\)

b: Ta có: \(2\left(3x-2\right)-4\left(x+6\right)+3\left(3-x\right)\)

\(=6x-4-4x-24+9-3x\)

\(=-x-19\)

c: Ta có: \(\left(x+y\right)^2+\left(x-y\right)^2-2x^2\)

\(=x^2+2xy+y^2+x^2-2xy+y^2-2x^2\)

\(=2y^2\)

Answer 2

d. (x - 3)² - (x - 3)(x + 3)\

= (x - 3)² - (x² - 9)

= (x - 3)² - x² + 9

= (x - 3 - x)(x - 3 + x) + 9

= -3(-3 + 2x) + 9

= 9 - 6x + 9

= 18 - 6x