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
Note that f(1) = 6(1)+2 = 8. Next, evaluate g(x) at x=8: g(f(1)) = g(8) = 2(8) + 4/5, or 16 4/5.
Answer:
15 inches
Tell me if you need me to explain
Solve x by simplifying both sides of the equation & then isolating the variable x=-4 & the negative comes in from the -12