Answer:
Step-by-step explanation:
b) a² - 1 + b(b - 2a) = a² -1 + b*b - b*2a {distributive property}
=a² - 1 + b² - 2ab
= (a² - 2ab + b² ) - 1
= (a - b)² - 1² {use identity x²-y²= (x+ y)(x -y)}
= (a - b + 1)(a -b +1)
b) 15 +8y + y² - 2x - x² = (y² + 8y + 15) - x² - 2x
= (y² + 5y + 3y + 15) - x(x + 2)
= [ y(y + 5) + 3(y +5)] - x(x + 2)
= [(y + 5)(y+3) ] - x(x +2)
