The sum of a certain two-digit number is 7. Reversing its digits increases the number by 9. What is the number?

34

Step-by-step explanation:

b=4 a=3

The first digit is 3 and the second 4 so the original number is 34

To be honest! It would be much quicker to solve by trial and error.

Explanation:

Building the equations

Let the first digit be  

a

Let the second digit be  

b

The first condition

a

+

b

=

7

(1)

Step-by-step explanation:

step-by-step explanation:

just plug in each number for x and see which ones work and don't

(1, –1), (16, –4), (36, –6)

step-by-step explanation:

given that the function is

this can also be written as

we have to graph this function and check which list of points lie on the graph

see attachment for graph:

we find that the points lying are (1,-1) (16,-4) and (36,-6)

since square root is there we find that x can only be posiitve but y can be since square root both positive and negative.