Answer:
B.) x² + 3x = 4
Explanation:
To find the answer, you need to (1) isolate "y" in the first equation and then (2) plug the rearranged first equation into the second equation.
(Step 1)
2y = 6x <----- Original first equation
y = 3x <----- Divide both sides by 2
(Step 2)
x² + y = 4 <----- Original second equation
x² + (3x) = 4 <----- Plug 3x in for "y"