You can put this solution on YOUR website! 3x + 7 = x^2 + k = 7x + 15
What is the value of k?
:
Two equations
Solve the one without the k
3x + 7 = 7x + 15
3x - 7x = 15 - 7
-4x = 8
x = 8/-4
x = -2
:
The equation with the k
x^2 + k = 7x + 15
:
Substitute -2 for x and find k:
(-2)^2 + k = 7(-2) + 15
4 + k = -14 + 15
4 + k = +1
k = 1 - 4
k = -3
:
Check: Substitute values for x and k in the original problem:
3x + 7 = x^2 + k = 7x + 15
3(-2) + 7 = (-2)^2 + -3 = 7(-2) + 15
-6 + 7 = 4 - 3 = -14 + 15; checks out
:
Did this make sense to you?
