How do you solve sqrt(2y + 7) + 4 = y?

1 Answer
Barney V.
Mar 18, 2018

y=9,y!=1

Explanation:

sqrt(2y+7)+4=y

:.(sqrt(2y+7))^2=(y-4)^2

:.2y+7=y^2-8y+16

:.2y+8y-y^2=16-7

:.10y-y^2=9

:.-y^2+10y-9=0

:.(-y+9)(y-1)=0

:.-y+9=0,y-1=0

:.-y=-9,y=1

:.y=9,y=1

~~~~~~~~~~~~~

check:-

substitute y=9

:.sqrt(2(9)+7)+4=(9)

:.sqrt(18+7)+4=9

:.sqrt25+4=9

:.5+4=9

:.9=9

substitute y=1

:.sqrt(2(1)+7)+4=(1)

:.sqrt(2+7)+4=1

:.3+4=1

no solution

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