Answer:
x = 4 or x = 12
Step-by-step explanation:
Given:
y = -10x² + 160x - 430
When y = $50
50 = -10x² + 160x - 430
50 + 430 = -10x² + 160x
480 = -10x² + 160x
-10x² + 160x - 480 = 0
Divide through by -10
x² - 16x + 48 = 0
Solve the quadratic equation using factorization method
+48 = -12 × -4
-16 = -12 -4
Therefore,
-12 and -4 are both factors
x² - 16x + 48 = 0
(x - 4 )(x - 12 ) = 0
x - 4 = 0
x = 4
OR
x - 12 = 0
x = 12
Answer:

Step-by-step explanation:

Answer:
4b represents the 4 bananas he eats
Answer: 104.5 seconds
Step-by-step explanation:
Hi, to answer this question we have to apply proportions:
Six students eat 6 apples in 33 seconds.
The proportion is: number of apples eaten /time
6 apples /33 seconds = 6/33
For 19 apples:
19 apples / x seconds =19/x
6/33 = 19/x
Solving for x:
x = 19 / ( 6/33)
x = 104.5 seconds
Feel free to ask for more if needed or if you did not understand something.