Answer:
3, 4
Step-by-step explanation:
x(x+1)=12
x^2+x-12=0
a=1, b=1, c=-12 in the quadratic formula
quadratic formula: ax^2+bx+c = 0
quadratic equation: x=(-b +/- √(b^2-4ac)) / 2a
= (-1 +/- √49 ) / 2
(-1 +/- 7) / 2
x= -4, x=3
-4 doesn't work because it is not positive
Therefore: Answer = 3, 4
It's the last choice. In the top row you have the 1's that are the coefficients on the x and the y, and the solution for that equation is 21; in the second row you have the 5 from the x and the 4 from the y and the solution for that equation which is 20. I'm more used to writing them down instead of across, but there you have it anyways
