Question

rút gon biểu thức :

(2x - 3)(x + 5) - x(2x + 7)

Answer 1

\(\left(2x-3\right)\left(x+5\right)-x\left(2x+7\right)\\ =2x^2-3x+10x-15-2x^2-7x\\ =\left(2x^2-2x^2\right)+\left(10x-3x-7x\right)-15\\ =-15\)

Answer 2

-15

Answer 3

\(\left(2x-3\right)\left(x+5\right)-x\left(2x+7\right)\\ =2x^2+10x-3x-15-2x^2-7x\\ =-15\)

Answer 4

\(\left(2x-3\right)\left(x+5\right)-x\left(2x+7\right)\)

\(=2x^2+10x-3x-15-2x^2-7x\)

\(=\left(2x^2-2x^2\right)+\left(10x-3x-7x\right)-15\)

\(=0+0-15\)

\(=-15\)