Simplify: $(y - 7) (y + 3)$

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Solution

$(y - 7) (y + 3)$
$= {y + (- 7)} (y + 3)$
[Using $(x - a) (x + b) = x^{2} + (b - a) x - a b$ ]
$= y^{2} + (- 7 + 3) y + (- 7) \times 3$
$= y^{2} - 4 y - 21$

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Simplify: (y−7)(y+3)

(y−7)(y+3)={y+(−7)}(y+3) [Using (x−a)(x+b)=x2+(b−a)x−ab]=y2+(−7+3)y+(−7)×3=y2−4y−21

Simplify: $(y - 7) (y + 3)$

$(y - 7) (y + 3)$
$= {y + (- 7)} (y + 3)$
[Using $(x - a) (x + b) = x^{2} + (b - a) x - a b$ ]
$= y^{2} + (- 7 + 3) y + (- 7) \times 3$
$= y^{2} - 4 y - 21$