2x+2/9y=26 ( ,18)

Question

I want to learn how to do these types of problems

Answer 1

Hi, Denvil.

When you have a problem with 2 variables, there is an infinite number of possible solutions. FYI, we can write them as ordered pairs (x,y) and graph them on the coordinate plane. In this case, because the variables do not have any exponents greater than 1, all the ordered pairs will form a straight line. But that's not what this problem is asking for.

In this problem, they give you one part of an ordered pair (  ,18) and you have to find the other part of it. So we need to substitute 18 in for y, and then solve for x.

2x + 2/9(18) = 26

2x + 4 = 26

2x = 22

x = 11

Hope this helps!

Answer 2

This isn't very clear, but I'm assuming the equation looks like the following:  (2x+2)/9y = 26

...and ( ,18) means that you are trying to solve for x since you are given y=18 ...?

If this is the case, you first want to set the equation equal to the variable you are trying to solve for. That is, rearrange the equation in a way that will isolate the unknown variable to one side of the equation, which will be in the form of    x =    .... 

To do this, first multiply both sides of the equation by 9y:

        9y * ((2x+2)/9y) = 9y * (26)     ==>     2x + 2 = 234y

Next, subtract 2 from both sides of the equation:

        2x + 2 - 2 = 234y - 2     ==>     2x = 234y - 2

Then divide both sides of the equation by 2:

        (2x) / 2 = (234y - 2) / 2     ==>     x = (234y)/2 - (2)/2

                                                           x = 117y - 1

The equation is now set to equal x. Since you are given y=18, plug in this value for y into the above equation to solve for x.

          x = 117y - 1

          x = 117(18) - 1

          x = 2106 - 1

          x = 2105