question 4 (a) simplify
3p -4r +7p -2r
= 3p + 7p = 10p
-4r    + -2r   = -6r
= 10p + -6r

(b) find the value of
5e -3f           
when   e = 3 and   f =  -7
5e =  5(3)
-3f = -3(-7)
=5(3) +-3(-7) 15 + -21

(c) expand
4(y -6)
= 4 (y) = 4y
= 4 (-6) = -24
= 4y + -21

(d) solve
6 -2x = 12
subtract - both sides by -6
= 6 -2x -6   = 12 -6
= 2x = 6
divide ÷ both sides 2
 ÷ 2/2x = 6/2  
=    x = -3