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Find the value of a+b when \(\left(a^2+2ab+b^2\right)\left(a+b\right)=125\)

 Apr 30, 2018
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(a + b)(a + b)  =  (a)(a) + (a)(b) + (b)(a) + (b)(b)  =  a2 + ab + ab + b2  =  a2 + 2ab + b2

 

So....   a2 + 2ab + b2  =  (a + b)(a + b)

 

And if

 

(a2 + 2ab + b2)(a + b)  =  125      then....

 

(a + b)(a + b)(a + b)  =  125

 

(a + b)3  =  125

 

a + b  =  \(\sqrt[3]{125}\)

 

a + b  =  5

 Apr 30, 2018

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