Answer:
x = 6
Step-by-step explanation:
If A, B and C lies on a straight line in order, then;
AB+BC = AC
x+12+2x-4 = 26
x+2x+12-4 =26
3x+8 = 26
3x = 26-8
3x = 18
x = 18/3
x = 6
Hence the value of x is 6
You find the x coordinates using x = -b/2a = -6/2(-1) = 3
Substitute 3 in the equation and find y
y = -(3^2) + 6(3) - 12 = -9 + 18 - 12 = -3
Vertex (3,-3)
The solution for your answer is 12
3.141562.... And it goes on and on and on
