Expert: Bobby Soltani - 7/17/2009

Question
Hi Bobby! i have a few problem that my pre-cal. teacher want
us to do over summer break and i got stuck on a few of these
questions.

these problem are to solve using square roots:
12x^2-48=0
(x-7)^2=5

these are to factor and solve:
2y^2=25y=13
x^2+14x+48=0
i get the factoring part but not the solve

these are to solve only:
square root of a^2+3a=2
(the symbol is over a^2+3a only)

sorry i know its alot cause my Alg. 2 teacher sucks at
teaching....i still passed his class though

Answer
Hi Kennedy,

I'll pick out a couple of these and solve them so you'll get the idea.

12x^2 - 48 = 0
isolate the x^2 term

add 48 to both sides

12x^2 = 48

divide both sides by 12

x^2 = 4

take the square root of both sides

x = 2 or -2

x^2+14x+48=0

we know that (x+a)^2 = x^2 + 2a + a^2.  Also we almost have this form if we let a=7, but we would need 49 to be the a^2 term, so we can add 1 to both sides

x^2 + 14x + 49 = 1

(x+7)^2 = 1

square root of both sides

x+7 = 1 or -1

x = -6 or -8

Let me know if you have any questions.

Bobby