Answer:
Step-by-step explanation:
Before we can calculate the equation of the parabola in the form
y = ax²+bx, we need to get the value of a and b.
First we need to set up a simultaneous equation as shown;
since y = ax²+bx
dy/de = y' = 2ax + b
Substitute the point (2, 8) into the equation
y' = 2a(2)+b
y' = 4a + b
Since y' is also the slope of the equation y = 12x-16, hence y' = 12 on comparison.
The equation becomes;
12 = 4a+b
4a+b = 12 ........... 1
Since the point (2, 8) is also on the parabola, then it must satisfy the equation y = ax²+bx
substitute the coordinate;
8 = a(2)²+b(2)
8 = 4a + 2b
4 = 2a + b
2a+b = 4 ........... 2
Solve equations 1 and 2 simultaneously
4a+b = 12 ........... 1
2a+b = 4 ........... 2
Substract both equation
4a - 2a = 12-4
2a = 8
a = 4
substitute a = 4 into equation 2 and get b;
From 2; 2a+b =4
2(4)+ b = 4
8+b = 4
b = 4-8
b = -4
Substitute a = 4 and b = -4 into the equation of the parabola y = ax²+bx
y = 4x²+(-4)x
y = 4x²-4x
y = 4x(x-1)
Hence the required equation of the parabola is y = 4x(x-1)
