Question
Evaluate $\left(-8 x^2 y^6\right) \times(-20 x y)$ for $x=2.5$ and $y=1$
✓
Answer
To multiply algebraic expressions, we use commutative and associative laws along with the law of indices, i.e. $a^m× a^n= a^{m+n}$.
We have:
$ \left(-8 x^2 y^6\right) \times(-20 x y) $
$ =[(-8) \times(-20)] \times\left(x^2 \times x\right) \times\left(y^6 \times y\right) $
$ =[(-8) \times(-20)] \times\left(x^2+1\right) \times\left(y^6+1\right) $
$ =160 x^3 y^7 $
$ \left(-8 x^2 y^6\right) \times(-20 x y)=160 x^3 y^7$
Substituting $x=2.5$ and $y=1$ in the result, we get:
$ =160 x^3 y^7 $
$ =160(2.5)^3(1)^7 $
$ =160 \times 15.625 $
$ =2500$
Thus, the answer is $2500$.
We have:
$ \left(-8 x^2 y^6\right) \times(-20 x y) $
$ =[(-8) \times(-20)] \times\left(x^2 \times x\right) \times\left(y^6 \times y\right) $
$ =[(-8) \times(-20)] \times\left(x^2+1\right) \times\left(y^6+1\right) $
$ =160 x^3 y^7 $
$ \left(-8 x^2 y^6\right) \times(-20 x y)=160 x^3 y^7$
Substituting $x=2.5$ and $y=1$ in the result, we get:
$ =160 x^3 y^7 $
$ =160(2.5)^3(1)^7 $
$ =160 \times 15.625 $
$ =2500$
Thus, the answer is $2500$.
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