Question

Exercitiul 7 ..d,e,f,g

Answer 1

$d)7 {y}^{5} + 21 {y}^{3} = 7 {y}^{3} ( {y}^{2} + 3)$

$e)4x(x - 1) - (1 - x) = 4x(x - 1) + x - 1 = (x - 1)(4x + 1)$

$f)y(2 - x) + 9(x - 2) = - y(x - 2) + 9(x - 2) = (x - 2)(9 - y)$

$g)5(a - b) + y {(b - a)}^{2}$

$= 5(a - b) + y{[ - (a - b)]}^{2}$

$= 5(a - b) + y \times {( - 1)}^{2} \times {(a - b)}^{2}$

$= 5(a - b) + y \times 1 \times {(a - b)}^{2}$

$= 5(a - b) + y {(a - b)}^{2}$

$= (a - b)[5 + y(a - b)]$

$= (a - b)(5 + ya - yb)$