What is the solution set?

Question

what is the solution set for 4x^2-30=2? I know we have to move the 2 over to the left so we have 4x^2-32=0. I don't know what to do next. Should i use the quadratic formula? Please help me. I have a test and I don't understand this. If possible can i get an explaination/steps?

Answer 1

We really do not need the quadratic formula here since the problem will factor.

 

4x^2-32=0     factor out the common factor of 4

 

4(x² - 8) = 0     divide both sides by 4

 

   x² - 8 = 0       add 8 to both sides

 

       x² = 8        take square root of both sides

 

       x = ±sqrt(8)    simplify sqrt 8

 

      x = ±2sqrt2