Question

The sum of the digits of a two-digit number is seven. When the digits are reversed, the original number is increased by nine. Find the number

Answer 1

I Really Need help on these 1

Answer 2

This is a system of equations problem. Suppose the number is AB. So

A + B = 7
10B +A = 10A + B +9

Can you solve that?

Answer 3

No

Answer 4

You haven't studied systems of equations?

Answer 5

not yet

Answer 6

my younger brother is having trouble with this problem and im trying to help him find the answer

Answer 7

OK, so we'll use one of the methods used for these problems, the substitution method.

Answer 8

ok

Answer 9

Take my first equation and rearrange it to A = 7 -B, then substitute it into the second problem.

Answer 10

ok

Answer 11

That gives us

10B +7 -B = 10(7 -B) + B +9

Answer 12

right

Answer 13

Note that we went from two variables to one. Can you solve that equation?

Answer 14

No i Cant

Answer 15

OK, then let's do it......

10B +7 -B = 10(7 -B) + B +9
9B + 7 = 79 - 9B
18B=72
B = 4
so, (by substitution into the equation A = 7-4 = 3) the number is 34.

Check step, reverse the digits, 43 is nine more.

Answer 16

oh i andurstand now thanks alot that really helped

Answer 17

No sweat.