Answer:
Credit remaining after 21 minutes = $30.4
Step-by-step explanation:
Credit remaining on a phone card is a linear function of the total calling time.
When graphed, let the linear function representing the line is,
y = mx + b
Where 'm' = slope of the line
b = y-intercept
From the graph,
Slope of the line = -0.12
y = -0.12x + b
If this line passes through a point (33, 28.96),
28.96 = -0.12(33) + b
b = 28.96 + 3.96
b = 32.92
Therefore, the linear function is,
f(x) = -0.12x + 32.92
where x = calling time
Credit left in the card after 21 minutes,
f(21) = -0.12(21) + 32.92
= -2.52 + 32.92
= $30.4
Step-by-step explanation:
Inflection points are where a function changes concavity (the second derivative changes signs). At x = 4, f"(x) goes from negative to positive, so that's an inflection point. However, at x = 8, we don't know if f"(x) changes signs or not. So we can't say that that's an inflection point.
Answer:
x=3/2,1
Step-by-step explanation:Given
(3x-2)ˆ5-(3x-2)ˆ2=0
(3x-2)ˆ3(3x-2)ˆ2-(3x-2)ˆ2=0
(3x-2)ˆ2{(3x-2)ˆ3-1}=0
(3x-2)ˆ2=0 Or (3x-2)ˆ3-1=0
3x-2=0 Or(3x-2)ˆ3=1
x=3/2 Or 3x-2=1, x=1
Theres an app called photomath that could easily solve problems like this
