Answer:
y = 15
Step-by-step explanation:
Even tho' we're supposed to find y here, it's easier to eliminate y first, find x and then go back and calculate y.
Both given formulas have already been solved for y:
y=5x-20 and y=x^2-9x+29
We can equate them: 5x-20 = x^2-9x+29.
Next, move the terms 5x - 20 to the right side:
0 = x^2-9x+29 - 5x + 20, or
0 = x^2 - 14x + 49
This last result is the square of a binomial: the square of x - 7.
Thus, there are two identical, real solutions: {7, 7}.
Now go back to y = 5x - 20, substitute 7 for x and calculate the y-coordinate:
y = 5(7) - 20 = 15
The y coordinate of the solution is 15.
