1.解方程
4(x+5)+8=80
4x+20+8=80
4x=52
x=13
2.化简求值
当x=12.5,y=2.5时,求2y+8x-8y的值.
2x 2.5+8 (12.5-2.5)=5+80=85
当a=2..5,b=0.8时,求6a-4b+4a-6b的值.
6a-4b+4a-6b=2a-10b=5+8=13
3.
(1) x比12大10,求x.
x-12=10
x=12+10=22
(2)x比15少6,求x.
x-15=-6
x=15-6=9
1.解方程
4(x+5)+8=80
4x+20+8=80
4x=52
x=13
2.化简求值
当x=12.5,y=2.5时,求2y+8x-8y的值.
2x 2.5+8 (12.5-2.5)=5+80=85
当a=2..5,b=0.8时,求6a-4b+4a-6b的值.
6a-4b+4a-6b=2a-10b=5+8=13
3.
(1) x比12大10,求x.
x-12=10
x=12+10=22
(2)x比15少6,求x.
x-15=-6
x=15-6=9