Simplify : 2t - 5m - 7t + 9m.

( 2 )

( b ) Solve the equation : 3(2a - 6) + 4(2 – 5a) = 18

( 3 )

( c ) Factorise completely : 15 p²q - 30pq²

1 answer

(a) 2t - 5m - 7t + 9m
= (2t - 7t) + (-5m + 9m)
= -5t + 4m

(b) 3(2a - 6) + 4(2 - 5a) = 18
6a - 18 + 8 - 20a = 18
-14a - 10 = 18
-14a = 28
a = -2

(c) Factorise completely: 15p^2q - 30pq^2
= 15pq(p - 2q)