Question

two times a number added to another number is 20. three times the first number minus the other number is 20. find the numbers

Answer 1

y=7

Explanation:

We have two numbers,

x

,

y

. We know two things about them:

2

x

+

y

=

25

3

x

−

y

=

20

Let's add these two equations together which will cancel the

y

:

5

x

+

0

y

=

45

x

=

45

5

=

9

We can now substitute in the

x

value into one of the original equations (I'll do both) to get to

y

:

2

x

+

y

=

25

2

(

9

)

+

y

=

25

18

+

y

=

25

y

=

7

3

x

−

y

=

20

3

(

9

)

−

y

=

20

27

−

y

=

20