-4(7a+5)= —160
distribute the -4 on the left hand side
-4* 7a + -4*5 = -160
-28a +-20 = 160
-28a -20 = -160
add 20 to each side
-28a-20+20 = -160 +20
-28a = -140
divide by -28 on each side
-28a/-28 = -140/-28
a = 5
Answer: a=5
1 ) 3 t ( t + 2 ) - 3 t² =
= 3 t² + 6 t - 3 t² = 6 t = 6 · 19 = 114
2 ) - ( 3 a - 2 b ) - 3 ( - a- b ) =
= - 3 a + 2 b + 3 a + 3 b = 5 b
