Jawabanmu

2014-09-10T18:56:42+07:00
2.a. 10 x (2y-10)= (10 . 2y)+(10 x -10) = 20y-100
b. (x+5)x(5x-1)=(x.5x) + (x . -1) + (5 x 5x)+(5.-1)=5x²-x+25x-5=5x²+24x-5
c.(7-2x)(2x-7)= (7 . 2x)+(7 . -7)+(-2x . 2x)+(-2x . -7)=14x-49-4x²+14x = -4x²+28x-49
3.(2x+3y)(px+qy)=rx²+23xy+12y²
   2px²+2qxy+3pxy+3qy²= rx²+23xy+12y²
   r = 2p