<span>Round this to the nearest hundred. 728
= 700</span>
The answer is x=-3
5-x=11+x
-11 -11 First subtract 11
-6-x=x
+x +x Now add x to both sides
-6=2x
~2 ~2 Finally divide by 2
-3=x Your answer is x=-3
Unit digit=y
tens digit=x
the number: 10x+y
We suggest this system of equations:
x+y=7
(10y+x)=(10x+y)+9
we solve it by substitution method.
x=7-y
10y+(7-y)=(10(7-y)+y)+9
9y+7=70-10y+y+9
9y+10y-y=70+9-7
18y=72
y=72/18=4
x=7-y
x=7-4=3
number=10x+y=10*3+4=30+4=34
solution: the number: 34
To check:
3+4=7
43=34+9
(x) = x – 2inverse of the function
