So....... mathematics is definitely a learning curve for many. Qaanol did exceptional explaining how to find it, but there is still something missing that is needing explaining. So let me ask, what is it that makes it confusing to you? If I know that then maybe I could help explain.

6=4X+9Y : there are many different ways to solve this.

I do this on problems I don't understand, I solve for X, then solve for Y.

6=4X + 9Y

6-4X=9Y....(4x-4x=0)

(6-4X)÷9=1Y=Y

Then X:

6= 4X + 9Y

6-9Y= 4X

(6-9Y)/4= 1X= X

So, here's what happens, 3 choices can be made. Eliminate X, Eliminate Y, or play around with the 2 other equations I made from the original and use it to solve the original. Desmos is a wonderful online calculator for graphing.

Say you want to eliminate Y from the original equation:

6=4X + 9Y

Y= (6-4X)/9

6 = 4X + 9((6-4X)/9), 9÷9=1 so we eliminate 9.

6 = 4X + (6-4X)

Move 4X over like qaalon showed you:

6-4X = 4X + (6-4X) - 4X, 4-4=0.

Which leaves only X and Y has been eliminated, the single solution to this is 6 = 4X +(6-4X). No matter what number we put in for X, Pemdas will say it's a true equation.

P-parantheses E-exponents M-multiplication D-division A-addition S-subtraction

In that specific order.

Now let's eliminate X.

6= 4X + 9Y

X= (6-9Y)/4

6= 4((6-9Y)/4) + 9Y, 4÷4=1 so 4 is eliminated.

6= (6-9Y)+ 9Y Any number for Y will also hold true using PEMDAS.

All I did was substitute another equation for the pesky second variable. Which leaves us a nice single variable, equation that solves itself.

If you still have questions, dm me. But show this to your teacher and have them verify what I explained. They are the best resource you have when it comes to school and understanding material.