Question

rút gọn các biểu thức sau: a, 5*(x-2)*(x+2)-5*(x^2*8) b,(a-b)^2+4ab

Giúp mình với!

 

 

 

Answer 1

\(a,5\left(x-2\right)\left(x+2\right)-5.x^{28}\)

\(=\left(5x-10\right)\left(x+2\right)-5x^{28}\)

\(=5x^2+10x-10x-20-5x^{28}\)

\(=5x^2-2x-5x^{28}\)

\(b,\left(a-b\right)^2+4ab\)

\(=a^2-2ab+b^2+4ab\)

\(=a^2+2ab+b^2\)

Answer 2

a) 5(x - 2)(x + 2) - 5.x²⁸

= 5(x² - 4) - 5.x²⁸

= 5.x² - 5.4 - 5.x²

= 5x² - 20 - 5x²⁸ 

= -5x²⁸ + 5x² - 20

b) (a - b)² + 4ab

= a² - 2ab + b² + 4ab

= a² - 2ab + b²

Answer 3

\(a,5\left(x-2\right)\left(x+2\right)-5x^{28}\)

\(=\left(5x-10\right)\left(x+2\right)-5x^{28}\)

\(=5x^2+10x-10x-20-5x^{28}\)

\(=5x^2-2x-5x^{28}\)

\(b,\left(a-b\right)^2+4ab\)

\(=a^2-2ab+b^2+4ab\)

\(=a^2+2ab+b^2\)