Jawapan

2015-10-15T00:19:13+08:00
1) 7ab -6ab +3ef -5ef
= ab -2ef

2) 4mn -3mn -2mp +7mp
= mn +5mp

3) r = -2, s = 5, t = 3

i) r (s +t) + r^2
= rs +rt + r^2
= (-2)(5) + (-2)(3) + (-2)^2
= -10 -6 +4
= -12

ii) 6st + 1 / 5 r^2 s - 2rt
= 6(5)(3) + (-2)^2 (5) /5 - 2(-2)(3)
= 90 + 20/5 -(-12)
= 90 +4 +12
= 106