Question

Решите 1075 пожалуйста

Answer 1

a)
$left { {{3(x-5)-1=6-2x} atop {3(x-y)-7y=-4}} right.$

$left { {{3x-15-1=6-2x} atop {3x-3y-7y=-4}} right.$

$left { {{3x+2x=15+1+6} atop {3x-10y=-4}} right.$

$left { {{5x=22} atop {3x-10y=-4}} right.$

$left { {{x=4,4} atop {3x-10y=-4}} right.$

$left { {{x=4,4} atop {3*4,4-10y=-4}} right.$

$left { {{x=4,4} atop {13,2-10y=-4}} right.$

$left { {{x=4,4} atop {10y=17.2}} right.$

$left { {{x=4,4} atop {y=1,72}} right.$

б) Вот с этим решением я не очень уверенна 
$left { {{6(x+y)-y=-1} atop {7(y+4)-(y+2)=0}} right.$

$left { {{6x+6y-y=-1} atop {7y+28-y-2=0}} right.$

$left { {{6x+5y=-1} atop {6y=2-28}} right.$

$left { {{6x+5y=-1} atop {6y=-26}} right.$

$left { {{6x+5y=-1} atop {y=4 frac{1}{3} }} right.$

$left { {{6x+5*4 frac{1}{3}=-1 } atop {y=4 frac{1}{3} }} right.$

$left { {{6x+21 frac{2}{3}=-1 } atop {y=4 frac{1}{3} }} right.$

$left { {{6x[tex] left { {{6x=-22 frac{1}{3} } atop {y=4 frac{1}{3} }} right.$

$left { {{x= frac{67}{18} } atop {y=4 frac{1}{3} }} right.$=-21 frac{2}{3}-1 } atop {y=4 frac{1}{3} }} right. [/tex]