Question

РЕШИТЕ СРОЧНО (3x+5)(4x-6), (5x-9y)(5x+9y), (0,72x+0,2)(0,6x-0,7) ОЧЕНЬ СРОЧНО

Answer 1

(3x+5)(4x-6)=12x²-18x+20x-30=12x²+2x-30

(5x-9y)(5x+9y)=(5x)²-(9y)²=25x²-81y²

(0,72x+0,2)(0,6x-0,2)=0,432x²-0,144x+0,12x-0,04=

0,432x²-0,024x-0,04

Answer 2

$(3x + 5)(4x - 6) = {12x}^{2} - 18x + 20x - 30 = {12x}^{2} + 2x - 30 = 2( {6x}^{2} + x - 15)$
$(5x - 9y)(5x + 9y) = {25x}^{2} + 45xy - {81y}^{2} - 45xy = {25x}^{2} - {81y}^{2}$
$(0.72x + 0.2)(0.6x - 0.7) = {0.432x}^{2} - 0.504x + 0.12x - 0.14 = {0.432x}^{2} - 0.384x - 0.14$