can you show me the format to get the answer to m/3 +4=7
we have

solve for m
that means
isolate the variable m
so
step 1
subtract 4 both sides

step 2
multiply by 3 both sides

therefore
the answer is
m=9
we have that
step 1
is equal to
m/3 +4-4=7-4
step 2
is equal to
m/3=3
step 3
is given
step 4
is given
Part 2
Let
n------> number of hours
y -----> the total charge
Remember that
The linear equation in slope intercept form is equal to
y=mx+b
where
m is the slope or unit rate
b is the y-intercept or initial value
In this problem
y=mn+b
where
m=$25 per hour
b=$50
so
y=25n+50
For y=$125
Find out the number of hours
substitute the value of y in the equation and solve for n
125=25n+50
25n=125-50
25n=75
n=3 hours
therefore
the answers are
the total charge's equation is (25n+50)
the number of hours are 3