Question

Thực hiện phép tính 

4(x + 5)(x – 5) – (2x – 7)²

Gấp nka mọi người 

Answer 1

\(4\left(x+5\right)\left(x-5\right)-\left(2x-7\right)^2\)

\(=4\left(x^2-25\right)-\left(4x^2-28x+49\right)\)

\(=4x^2-100-4x^2+28x-49\)

\(=4x^2-4x^2+28x-100-49\)

\(=28x-149\)

Answer 2

\(=4\left(x^2-25\right)-4x^2-28x+49\)

\(=4x^2-100-\left(4x^2-28x+49\right)\)

\(=4x^2-100-4x^2+28x-49\)

\(=-149+28x\)