Answer:
i.e answer A.
Step-by-step explanation:
This question involves knowing the following power/exponent rule:
![\sqrt[n]{x^m} = x^\frac{m}{n} \\\\so \sqrt[7]{x^2} = x^\frac{2}{7} \\\\and \\\\ \sqrt[5]{y^3} = y^\frac{3}{5} \\](https://tex.z-dn.net/?f=%5Csqrt%5Bn%5D%7Bx%5Em%7D%20%3D%20x%5E%5Cfrac%7Bm%7D%7Bn%7D%20%5C%5C%5C%5Cso%20%5Csqrt%5B7%5D%7Bx%5E2%7D%20%3D%20x%5E%5Cfrac%7B2%7D%7B7%7D%20%5C%5C%5C%5Cand%20%20%5C%5C%5C%5C%20%5Csqrt%5B5%5D%7By%5E3%7D%20%3D%20y%5E%5Cfrac%7B3%7D%7B5%7D%20%5C%5C)
Next, when a power is on the bottom of a fraction, if we want to move it to the top, this makes the power become negative.
so the y-term, when moved to the top of the fraction, becomes:

So the answer is: 
Answer:
5x^2 + xy + 20
Step-by-step explanation:
Begin with 5x^2+3xy+12, Subtracting 2xy yields 5x^2 + xy + 12. Next, subtracting -8 yields 5x^2 + xy + 12 - (-8), or 5x^2 + xy + 20
Step-by-step explanation:
factor 4 out of the variable terms, as this helps.
but my approach is simply to define the target and then calculate "backwards".
we want to find
(ax + b)² = a²x² + 2abx + b²
and now we compare with the original equation :
a²x² = 4x²
a² = 4
a = 2
2abx = 16x
2×2×bx = 16x
4b = 16
b = 4
b² = 16, but we have only 3, so we need to subtract 16-3 = 13 from the completed square.
so, our equation is
(2x + 4)² - 13 = 0
(2x + 4)² = 13
2x + 4 = sqrt(13)
2x = sqrt(13) - 4
x = sqrt(13)/2 - 2
You can probably look up a answer key for that worksheet. ;)