Answer:
25m + 10b = 400
Step-by-step explanation:
Total amount that can be earned = $ 400
Amount earned on mowing a lawn = $ 25
Amount earned per hour on babysitting = $10
Amount earned for mowing one lawn is $ 25, so amount earned for mowing m lawns will be $ 25m
Amount earned for one hour of babysitting is $ 10, so amount earned for babysitting for b hours will be $ 10b
Total amount earned = Amount earned from mowing m lawns + Amount earned from babysitting for b hours
Using the values from above, we can set up the equation as:
400 = 25m + 10b
or
25m + 10b = 400
This equation represents the number of lawns they can mow, m, and hours they can babysit, b, to earn $400.
Perimeter of rectangle = 2(l+w)
So, 54cm = 2(l+9cm)
=> 54cm = 2l + 18cm
=> 54cm - 18cm = 2l
=> 36cm = 2l
=> 36cm/2 = l
=> 18cm = l
Standard form of an exponential function is y=ab^x
when x=0, y=3, 3=ab^0, so you can figure out that a=3
when x=-1, y=6, 6=3b^(-1), b^(-1)=2, b=1/2
so the equation is y=3(1/2)^x
