Bryan has a prepaid cell phone with a balance of $75. He is charged the same rate per minute. Which function represents the bala
1 answer:
You might be interested in
Answer:
a = 2, b = - 5
Step-by-step explanation:
Given
y = ax² + bx
is the measure of the slope at x = a
Differentiate each term with respect to x using the power rule
(a
) = na
= 2ax + b, hence
2ax + b = 3 at (2, - 2)
Substitute x = 2 into
4a + b = 3 → (1) and substitute x = 2 into y
4a + 2b = - 2 → (2)
Subtract ( 1) from (2)
b = - 2 - 3 = - 5
Substitute b = - 5 into (1)
4a - 5 = 3 ( add 5 to both sides )
4a = 8 ( divide both sides by 4 )
a = 2