04 Jul, 2021 12:58 PM

What are the solutions of the equation (x + 2)2 – 2(x + 2) – 15 = 0? Use u substitution to solve. x = –7 and x = 1 x = –5 and x = 3 x = –3 and x = 5 x = –1 and x = 7

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BE
04 Jul, 2021 12:58 PM
The given equation is[tex] (x+2)^2 -2(x+2)-15=0 [/tex][tex] let \ u \ = \ x+2 [/tex]So we will get[tex] u^2 -2u-15=0 [/tex]Factoring the left side[tex] (u-5)(u+3)=0 [/tex][tex] u-5=0, u +3 =0 [/tex]Solving both equations for u[tex] u= 5, -3 [/tex]Performing back substitution[tex] x+2 = 5, x+2 =-3\\x = 3, -5 [/tex]And that's the required solutions .
MA
04 Jul, 2021 12:58 PM
Answer:B.) x = –5 and x = 3