Question

$$6(x+1)^{2}+2(x-1)(x^{2}+x+1)-2(x+1)^{3}=32;$$

Answer

x=5

Solution


Expand.
\[6{x}^{2}+12x+6+2{x}^{3}+2{x}^{2}+2x-2{x}^{2}-2x-2-2x({x}^{2}+2x+1)-2({x}^{2}+2x+1)=32\]
Simplify  \(6{x}^{2}+12x+6+2{x}^{3}+2{x}^{2}+2x-2{x}^{2}-2x-2-2x({x}^{2}+2x+1)-2({x}^{2}+2x+1)\)  to  \(6{x}^{2}+12x+4+2{x}^{3}-2x({x}^{2}+2x+1)-2({x}^{2}+2x+1)\).
\[6{x}^{2}+12x+4+2{x}^{3}-2x({x}^{2}+2x+1)-2({x}^{2}+2x+1)=32\]
Expand.
\[6{x}^{2}+12x+4+2{x}^{3}-2{x}^{3}-4{x}^{2}-2x-2{x}^{2}-4x-2=32\]
Simplify  \(6{x}^{2}+12x+4+2{x}^{3}-2{x}^{3}-4{x}^{2}-2x-2{x}^{2}-4x-2\)  to  \(6x+2\).
\[6x+2=32\]
Subtract \(2\) from both sides.
\[6x=32-2\]
Simplify  \(32-2\)  to  \(30\).
\[6x=30\]
Divide both sides by \(6\).
\[x=\frac{30}{6}\]
Simplify  \(\frac{30}{6}\)  to  \(5\).
\[x=5\]