Question

4. Descompuneți în factori:
a) 25x² - 16y²
7x4 +56x =
b)
c) 25a² + 30ab + 9b²
=

Answer 1

$a)25x^2 - 16y^2 = (5x)^2 - (4y)^2=(5x-4y)(5x+4y)$

$b)7*4+56x=28+56x=28(1+2x)$

$c)25a^2+30ab+9b^2=(5a)^2+2*(5a)*(3b)+(3b)^2=(5a+3b)^2$

Teorie:

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