Question

(x - 5)/4 + (2x - 11)/3 = 7 (2 - 7y)/6 + (4y + 7)/3 = - y/3​

Answer 1

Ответ:

1) $\frac{x-5}{4} +\frac{2x-11}{3} =7;$

[ умножим обе части уравнения на 12 ]

$12 *\frac{x-5}{4} +12*\frac{2x-11}{3} =7*12;\\\\ 3(x-5)+4(2x-11)=84;\\\\ 3 * x - 3 * 5 + 4 * 2x - 4 * 11 = 84;\\\\ 3x - 15 + 8x - 44 = 84;\\\\ 11x - 59 = 84;\\\\ 11x = 84 + 59;\\\\ 11x = 143;\\\\ x=143:11;\\\\ x = 13.$

2) $\frac{2-7y}{6} +\frac{4y+7}{3} =-\frac{y}{3} ;$

[ умножим обе части уравнения на 6 ]

$6*\frac{2-7y}{6} +6*\frac{4y+7}{3} =-\frac{y}{3}*6 ;\\\\2-7y+2(4y+7)=-2y;\\\\2-7y+2 * 4y+ 2 * 7 = -2y;\\\\2-7y + 8y + 14 = -2y;\\\\16+y = -2y;\\\\y + 2y = -16;\\\\3y= -16;$

$y= -\frac{16}{3}=-5\frac{1}{3} .$