y = -5x + 24
y = 4x - 21
Since both of these equations are equal to Y, theyre equal to each other.
So we can make an equation with y = -5x + 24 in one side and y = 4x - 21 on the other.
-5x + 24 = 4x - 21
Now in order to get the value of x we need to isolate it in one side of the equation. We can do this by subtracting 24 from both sides of the equation:
-5x + 24 - 24 = 4x - 21 - 24
-5x = 4x - 45
Now we subtract 4x from both sides so the 4x shift to the other side
-5x - 4x = 4x - 4x - 45
-9x = -45
Finally divide both sides by -9 so x is by itself
(-9)÷(-9x) = -(45)÷(-9)
x = 5
Since we did all of this to BOTH sides of the equation, both sides are still equal to each other and the equation still is true.
Now apply x = 5 to either of the initial equations to find the value of Y
y = -5x + 24 or y = 4x - 21
(I'll do both but u only need one)
y = -5(5) + 24
y = -25 + 24
y = -1
y = 4(5) - 21
y = 20 - 21
y = -1
Either way, X is 5 and Y is -1
Answer (5, -1)