Help solve both of these questions

Let's solve for a.
p
x
=
x
3
−
4
x
2
+
a
Step 1: Flip the equation.
x
3
−
4
x
2
+
a
=
p
x
Step 2: Add -x^3 to both sides.
x
3
−
4
x
2
+
a
+
−
x
3
=
p
x
+
−
x
3
−
4
x
2
+
a
=
−
x
3
+
p
x
Step 3: Add 4x^2 to both sides.
−
4
x
2
+
a
+
4
x
2
=
−
x
3
+
p
x
+
4
x
2
a
=
−
x
3
+
p
x
+
4
x
2

a
=
−
x
3
+
p
x
+
4
x
2

200 miles.45 x 3 (charge per day times days)135$205$ - 135$ = 70$0.35x = 70divide both sides by 0.35200

Could you make it more clear?