The vertex of a quadratic function is (6, 2), and the y-intercept of the function is (0, -70). The equation of the function in vertex form, fx)=a(x-h' +k, is shown.
What is the value of a?

First step is to get rid of the square root. remember that a square root is the same as raising to the (1/2) power. see below: multiply exponents per exponent rules to get: remember you subtract exponents from the denominator and add exponents in the numerator so: simplify further: so a is the correct choice. if you don't understand this google exponent rules and it will you understand. look at the image results.

Iam not sure but i think the answer is b