The equation is
.
Apply distributive property:
.

(Multiply:
)
Apply addition property of equality: If a = b then a + c = b + c.
\
(Add 7 to each side)
(Apply additive inverse property:
)
(Apply additive identity property:
)
(Add: 35 + 7 = 42)
Apply division property of equality: if a = b then 
(Divide each side by 14)
(Cancel common terms)
(Divide:
)

Check:
\To substitute
in
.
(Substitute p = 3)
(Multiply:
)
(Subtract:
)
(Multiply:
)
The equality is true.
The solution is
.