step by step,easily understood by kids

 

1)32x+30=58y+44

32x<3000

58y+44<3000

2)simplify first step

We get y+x-7=15*(2y-x)

X<93

Y<51

3)

From the fact sentence y+x-7=15*(2y-x)

We know when 2y-x=1, then y+x-7=15 same as x+y=22

When2y-x=2, then y+x-7=30 same as x+y=37……ect.

Until 2y-x=9,then y+x-7=135 same as x=y=142( x<93,y<51, the highest possible x+y<144)

Total 9  possibilities.

4) calculate each possibility we get

3y=23,3y=39,3y=55,3y=71,3y=87,3y=103,3y=119,3y=135,3y=151.

Only 3y=39,3y=87,3y=135 we can get  integer for y.y=13,29,45.correspondingly we get the numbers 798,1726,2654.

所有跟帖： 

• 晚上回来和孩子一起学习！谢谢老师！ -风轻云淡水一方- ♀ (0 bytes) () 04/17/2014 postreply 09:24:20