Question

select the correct answer. which expression is equivalent to the given expression? (7y^6)(2y^ - 4)^2

1. $\frac{14}{y^{48}}$
2. $\frac{28}{y^{2}}$
3. 14
4. $28y^{14}$

Explanation:

Step1: Expand $(2y^{-4})^2$

$(2y^{-4})^2=2^2\times(y^{-4})^2 = 4y^{-8}$

Step2: Multiply with $7y^6$

$(7y^6)\times(4y^{-8})=(7\times4)\times y^{6+( - 8)}=28y^{-2}=\frac{28}{y^{2}}$

Answer:

$\frac{28}{y^{2}}$ (corresponding to the second - option in the multiple - choice list)