Question
Simplify:
$ (4.5 a+1.5 b)^2+(4.5 b+1.5 a)^2$
$ (4.5 a+1.5 b)^2+(4.5 b+1.5 a)^2$
✓
Answer
$ (4.5 a+1.5 b)^2+(4.5 b+1.5 a)^2$
$ =(4.5 a)^2+(1.5 b)^2+2 \times 4.5 a \times 1.5 b+(4.5 b)^2+(1.5 a)^2+2 \times 4.5 b \times 1.5 a $
$ =20.25 a^2+2.25 b^2+13.5 a b+20.25 b^2+2.25 a^2+13.5 a b $
$ =40.5 a^2+4.5 b^2+27 a b $
$ =(4.5 a)^2+(1.5 b)^2+2 \times 4.5 a \times 1.5 b+(4.5 b)^2+(1.5 a)^2+2 \times 4.5 b \times 1.5 a $
$ =20.25 a^2+2.25 b^2+13.5 a b+20.25 b^2+2.25 a^2+13.5 a b $
$ =40.5 a^2+4.5 b^2+27 a b $
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