Question

解方程组:y=1-x,3x+2y=5

Answer 1

y=1-x 带入3x+2y=5得 3x+2（1-x）=5 3x+2-2x=5 x+2=5 x=3 将x=3带入y=1-x y=-2 {x=3 y=-2

Answer 2

将y=1-x 代入等于3x +2（1-x ）=5 ,5= 3x +2-2x,5=3x-2x+2,x=3,将x=3,y=1-x代入, 得x=3,y=-2