(x+2y)² - (x-2y)² = (2x+1)(4y+3) (2x+3)/2 – (x-2y)/2 = 3(2x-y)/4 / *4 x² + 4xy + 4y² - (x² - 4xy + 4y²) = 8xy + 6x + 4y +3 2x + 3 -2(x-2y) = 3(2x-y) x² + 4xy + 4y² - x² +4xy - 4y² - 8xy - 6x - 4y = 3 2x 3 – 2x = 4y = 6x – 3y -6x – 4y = 3 6x – 3y – 4y = 3 -6x – 4y = 3 6x – 7y = 3 ---------------- dodajemy stronami -11y = 6 /: (-11) y = - 6/11 6x – 7 * (-6/11) = 3 6x + 42/11 = 3 6x = 3 – 42/11 6x = 3 – 3 i 9/11 6x = -9/11 / : 6 x= -9/11 :6 = - 9/11 * 1/6 x = - 3/22
(x+2y)2-(x-2y)2=(2x+1)(4y+3) (2x+3)/4-(x-2y)/2=3(2x-4)/4 x2+4y2+4xy-(x2+4y2-4xy)=8xy+6x+4y+3 (2x+3)/4-(x-2y)/2=3(2x-4)/4 /*4 x2+4y2+4xy-2x-4y2+4xy=8xy+6x+4y+3 2x+3-2(x-2y)=3(2x-4) x2-x2+4y2-4y2+4xy+4xy-8xy-4y=6x+3 2x+3-2x+4y=6x-12 -4y=6x+3 3+4y=6x-12 -4y=6x+3 3+4y-4y=6x-12+6x+3 -4y=6x+3 3=12x-12+3 12x=12 x=1 -4y=6*1+3 -4y=9/-4 y=-2,25