need to complete equations?

2007-10-31 3:54 am
9- ? =2+4

15-8=4+?

don't understand i'm 4th grade

回答 (8)

2007-10-31 4:03 am
✔ 最佳答案
First, solve the side of the equation with NO question mark.
9 - ? = 6
Now instead of subtracting ?, subtract 6 from both sides
9 - 6 = 6 - 6
9 - 6 = ?
If you know 9-6 is 3, then you know ? = 3.

Same idea with the next one.
7 = 4 +?
7 - 4 = ?
? = 3

I'm hoping this didn't make it more confusing.
2007-10-31 4:35 am
this question means that ...

1) 9-?=2+4(means the both the sides r equal so..)
9-?=6 (let the quetion mark be "x")
x=9-6
x=3(so the answer is 9-3=2+3
6=6).


2) 15-8=4+?(same as above)
7=4+x( let the "?" be 'x')
7-4=x
3=x
:. x=3(so the answer is 15-8=4+3
7=7)
2007-10-31 4:28 am
9-3 = 6
7 = 4+3
2007-10-31 4:01 am
9-?=6 transfer 9 tothe left side then change sign
-?=6-9 combine 6& -9
-?=-3 divide both side by -1 to eliminate negativity
therefore, ?=3

15-8=4+?
7=4+? transfer 4 to th left side then change sign
7-4=?
3=?
therefore, ?=3
2007-10-31 4:01 am
first switch the question marks to x
#1if you have 9-n=2+4 then u first add 2+4 which is 6. so then you're left with 9-n=6 then u subtract each side by 9 so you have 6-9(which equals -3). -3=-n then divide by negative one and you're left with 3=n
#2 15-8=4+n first do 15-8 which is 7 so you're left with 7=4+n then subtract four from both sides and you have 3=n.
That help you out at all ?
2007-10-31 4:00 am
Use a letter instead of a ? its a little easier to understand

9 - n = 2 + 4
9 - n + n = 2 + 4 + n
9 = 6 + n
9 - 6 = 6 + n - 6
3 = n

9 - 3 = 2 + 4
6 = 6

15 - 8 = 4 + n
7 = 4 + n
7 - 4 = 4 + n - 4
3 = n

15 - 8 = 4 + 3
7 = 7
2007-10-31 3:57 am
1rst answer= 4

2nd answer= 3
參考: hope that helped man
2007-10-31 3:57 am
9-3
4+3


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