Problem: its a systems of equations. please help solve. 3x+2y=4, y=2x+9
i cant figure it out D:
1) 3x + 2y = 4
2) y = 2x + 9
Equation 2 already shows us the value of y, in terms of x. Substitute
that into equation 1 and solve for x.
3x + 2y = 4
3x + 2(2x + 9) = 4
3x + 4x + 18 = 4
7x + 18 = 4
7x + 18 - 18 = 4 - 18
7x = -14
7x/7 = -14/7
x = -2
Now, solve for y.
y = 2x + 9
y = 2(-2) + 9
y = -4 + 9
y = 5
Check them.
3x + 2y = 4
3(-2) + 2(5) = 4
-6 + 10 = 4
4 = 4
Answer: x = -2, y = 5