Question

УМОЛЯЮ 4,6,7 ЗАДАНИЕ
СРОЧНО

Answer 1

$4)\; \; 9(x-2)^2-1=\Big (3(x-2)-1\Big )\Big (3(x-2)+1\Big )=(3x-7)(3x-5)\\\\\\27(x+7)^2-3=3\cdot \Big (9(x+7)^2-1\Big )=3\cdot \Big (3(x+7)-1\Big )\Big (3(x+7)+1\Big )=\\\\=3\cdot (3x+20)(3x+22)$

$6)\; \; 1243^2-757^2=(1243-757)(1243+757)=486\cdot 2000=972\, 000$

$7)\; \; (3x-1)^2+(4x+2)^2=(5x-1)(5x+1)\\\\9x^2-6x+1+16x^2+16x+4=25x^2-1\\\\10x+5=-1\\\\10x=-6\\\\x=-\frac{6}{10}\\\\x=-\frac{3}{5}\\\\x=-0,6$