Question

1. $left { {4x-5y=10} atop {3x+2y=19}} right.$ (Методом подстановки.)
2. $left { {2x-2y=7} atop {3x+2y=3} right.$ (Методом сложения.)
3. $left { {{2+3(x+5y)=-(2x+3y)} atop {3x+4y=-8}} right.$ (Любым методом.)

Помогите решить хоть что-то из этого...

Answer 1

1.
$left { {{4x-5y=10} atop {2x-2y=19}} right. ; left { {{2(19+2y) -5y=10} atop {x= frac{19+2y}{2} }} right. ; left { {{y=2} atop {x= frac{19+2y}{2} }}} right. ; left { {{38+4y-5y=10} atop {x= frac{19+2y}{2}}} right. ; left { {{-y=-28} atop {x= frac{19+2y}{2}}} right.$
$left { {{y=28} atop {x= frac{19+2*28}{2}}} right. ; left { {{x= frac{75}{2} } atop {y=28}} right.$

2.
$left { {{2x-2y=7} atop {3x+2y=3}} right. ; left { {{2x-2y=7} atop {2x+3x=7+3}} right. ; left { {{2x-2y=7} atop {5x=10}} right. ; left { {{x=2} atop {2*2-2y=7}} right. ; left { {{x=2} atop {-4y=3}} right. ; left { {{x=2} atop {y= -frac{3}{4} }} right.$

3.
$left { {{2+3(x+5y)=-(2x+3y)} atop {3x+4y=-8}} right. left { {{3x+2x+15y+3y=-2} atop {3x+4y=-8}} right. left { {{5x+18y=-2} atop {y= frac{-3x-8}{4} }} right.$
$left { {{5x+18*frac{-3x-8}{4}=-2} atop {y= frac{-3x-8}{4} }} right. left { {{5x-9*frac{3x+8}{2}=-2|*2} atop {y= frac{-3x-8}{4} }} right. left { {{10x-9(3x+8)=-4} atop {y= frac{-3x-8}{4} }} right.$
$left { {{10x-18x-72=-4} atop {y= frac{-3x-8}{4} }} right.left { {{-8x=68} atop {y= frac{-3x-8}{4} }} right.left { {{ x=-frac{17}{2} } atop {y= frac{3* frac{17}{2} -8}{4} }} right.left { {{ x=-frac{17}{2} } atop {y= frac{3*17-8*2}{4*2} }} right.left { {{ x=-frac{17}{2} } atop {y= frac{35}{8} }} right.$