Answer:
{5, -3} {0, -1/3}
Explanation:
For the first problem, they all have a GCF of 2, so you divide it all by 2 to get x^2-2x-15=0. Now, we need two factors of -15 that equal -2. Those are -5 and 3. Our new equation is x^2-5x+3x-15. To factor, the GCF of x^2 and 5x is x, so divide by x and you get x(x-5). The GCF of 3x and 15 is 3, so divide by 3 and you get 3(x-5). Now, put the numbers outside of the parenthesis into their own, and you get (x+3)(x-5). To get to 0, for the first one x has to be -3, and for the second, x has to be 5.
For the second, 12x^2 and 4x have a GCF of 4x. Since this we don't have a c value, we just divide and factor like this: 4x(3x+1). Since 4x is outside the parenthesis but we don't have any other terms outside, x=0 because 4(0) is 0. To cancel out 1, our x value inside has to be -1/3, because -1/3*3=-1.
Hope this helped!