Question

Решите систему уравнений методом подстановки:
а) {4x-5y=10
3x+2y=19
б) {2+3(x+5y)=-(2x+3y)
3x+4y=-8

Answer 1

$left { {{4x-5y=10} atop {3x+2y=19}} right. \ left { {{4x=5y+10} atop {3x+2y=19}} right. \ left { {{x=1,25y+2,5} atop {3x+2y=19}} right. \ 3*(1,25y+2,5)+2y=19\ 3,75y+7,5+2y=19\ 5,75y=11,5\ y=2\ x=1,25*2+2,5=5$

$left { {{2+3(x+5y)=-(2x+3y)} atop {3x+4y=-8}} right. \ left { {{2+3(x+5y)=-(2x+3y)} atop {4y=-8-3x}} right. \ left { {{2+3(x+5y)=-(2x+3y)} atop {y=-2-0,75x}} right. \ 2+3(x+5*(-2-0,75x)=-(2x+3*(-2-0,75x))34\ 2+3x-30-11,25x=-2x+6+2,25x\ -28-8,25x=6+0,25x\ 8,5x=-34\ x=-4\ y=-2-0,75*(-4)=1$