Jawab:
Penjelasan dengan langkah-langkah:
a. (2x-4) (3x+5) == 2x( 3x+5) - 4(3x + 5)= 6x² + 10x - 12x - 20= 6x² - 2x - 20
b. (2x + 3) (4x-5) == 2x(4x -5) + 3(4x -5)= 8x² - 10x + 12x - 15= 8x² + 2x - 15
c. 2(4x-5)-5x+7 == 9x -10 - 5x + 7= 4x - 3
d. (-2x+3)(-2x-3) == -2x( -2x - 3) + 3(-2x - 3)= 4x² + 6x - 6x - 9= 4x² - 9
e. -3p(-4q+5r) =
= 12 pq - 15 pr
f. (3x-4y)(4x + 3y) =
= 3x (4x + 3y) - 4y (4x+ 3y)= 12 x² + 9 xy - 16xy- 12 y²= 12 x² - 7 xy - 12y²'
g. (5y + 7)(7-5y)=
= 5y(7 -5y) + 7(7- 5y)= 35y - 25y² + 49- 35y= -25y² + 49