In this question, the given functions are
And we have to find the value of
Which is equal to
So we have to subtract the two functions that is
Correct option is the second option .
This is wrong DONT use it
Answer: 9 * (5 - y)
Explanation:
Times: multiplication
Difference: subtraction
y: the unknown variable
Recall that the slope is the "average rate of change" of any function.

Answer:
For every 7 hair bands there will be 4 ribbons
7 hair bands →→ 4 ribbons
14 hair bands →→ 8 ribbons
21 hair bands →→ 12 ribbons
etc.
Let's V the speed of the girl in step
v the speed of the escalator in step
L the length between ground and floor.
V*60+v*60=L ==> V+v=L/60
V*90-v*90=L ==> V-v=L/90
2V=L(3+2)/180
==>V=5L/360
Time to climb (in step) with v=0 (escalator standing still)
V*t=L==> t=L/V=L/(L*5/360)=72
The girl will count 72 steps.