Jawabanmu

2014-09-12T12:31:32+07:00
A.6x-11y-17
b 1y²-19xy
c 12p²q+10pq-13p²+12
1 4 1
2014-09-12T12:37:21+07:00
A.(8x-9y-21)-(2x+2y-14)
=8x-9y-21-2x-2y+14
=8x-2x-9y-2y-21+14
=6x-11y-7

b.3y(y-5x)-(2y^2+4xy)
=3y^2-15xy-2y^2-4xy
=3y^2-2y^2-15xy-4xy
=y^2-19xy

c.(12p^2q+8pq)-(13p^2-2pq-12)
12p^2q+8pq-13p^2+2pq+12
=12p^2q+8pq+2pq-13p^2+12
=12p^2q+10pq-13p^2+12

Catatan : ^2=²
4 3 4