1. 4x^2-13x=12

I need to solve this problem by factoring or using the quadtratic formula. I am stuck when using the quadtratic formula method. Please advise how to do this.

2. 5x^2+42=0
How many roots exist in this equation and what type are they?

1. 4x^2-13x -12 = 0

Playing around a bit with the pairs 4&3 and 6&2 as the constants, I get
(4x + 3)(x -4) = 0
That makes the roots x=-3/4 and 4

2. x^2 = -42/5
There are two imaginary roots that have an "i" (sqrt(-1) factor