Question

Математика,6 класс,задание 875

Answer 1

$1)\;\frac{x-5}4=7-\frac{2x-11}3\\\frac{x-5}4=\frac{21-2x+11}3\\\frac{x-5}4=\frac{32-2x}3\\3x-15=128-8x\\3x+8x=128+15\\11x=143\\x=13\\\\2)\;5+\frac{7x-12}3=x+13\\\frac{15+7x-12}3=x+13\\7x+3=3x+39\\ 7x-3x=39-3\\4x=36\\x=9\\\\3)\;\frac{2-7y}6+\frac{4y+7}3=-\frac y2\;\;\;\times6\\2-7y+8y+14=-3y\\y+3y=-2-14\\4y=-16\\y=-4\\\\4)\;\frac{7y-1}{12}-\frac{y+1}4=\frac{2y+5}3\;\;\;\times12\\7y-1+3y-3=8y+20\\10y-8y=20+4\\2y=24\\y=12$