1.设地上为x只,树上为y只.
列方程:3(x-4)=y+4 (1)
2(x+4)=y-4 (2)
(1)-(2) x-12-8=8
x=28
y=68.
2.设甲现在x岁,乙为y,
列方程:x-y=y-4 (1)
61-x=x-y (2)
x=42.
y=23.
1.设地上为x只,树上为y只.
列方程:3(x-4)=y+4 (1)
2(x+4)=y-4 (2)
(1)-(2) x-12-8=8
x=28
y=68.
2.设甲现在x岁,乙为y,
列方程:x-y=y-4 (1)
61-x=x-y (2)
x=42.
y=23.