Question

(x+3)(x+7)-(x+4)^2=0
(y+8)^2-(y+9)(y-5)=117

Answer 1

$1)(x+3)(x+7)-(x+4) ^{2} =0 \ x^{2} +3x+7x+21- (x^{2} +16+8x)=0\ x^{2} +10x+21- x^{2} -16-8x=0 \ 2x+5=0 \ 2x=-5 \ x=- frac{5}{2} \ x=-2.5$

$2)(y+8) ^{2} -(y+9)(y-5)=117\y ^{2} +64+16y-(y ^{2} -5y+9y-45)=117 \ y ^{2} +64+16y-(y ^{2} +4y-45)=117\y ^{2} +64+16y-y ^{2} -4y+45=117\16y-4y=117-64-45\12y=8 \ y= frac{8}{12} \ y= frac{2}{3}$