Answer:
The monthly cost for 45 minutes is $18.42
Step-by-step explanation:
Let
x -----> the total calling time in minutes
y ----> the monthly cost in dollars
we have the ordered pairs
(42,18.15) and (90,22.47)
step 1
Find the slope
The formula to calculate the slope between two points is equal to
substitute the values
step 2
Find the linear equation in point slope form

we have

substitute

step 3
Find the monthly cost for 45 minutes of calls
For x=45 min
substitute the value of x in the linear equation and solve for y





therefore
The monthly cost for 45 minutes is $18.42
Answer:
B and D
Step-by-step explanation:
To find the percentage, you divide Martin's correct answers by the total number of questions, then multiply the result by 100.
To find the fraction, it's <em>correct answers/total questions</em>.
2(x+4)=2x+8=-7-3x switch 3x+2x=-7-8=-15=5x so x=-15/5=-3