Simeltaneous Equasions

Welcome to the forums.

On problems like this there are at least a couple of approaches. You can graph both lines and see where they intersect.

The classic method is substitution. Take either equation and solve for one of the variables, then substitute into the other.

To illustrate the methodolog of substitution, suppose you have the following:

x + 2y = 5
x - y = -1

Step 1: solve the second equation for y:

y = x + 1

Step 2: substitute the result into the 1st equation:

x + 2(x + 1) = 5
x + 2x + 2 = 5
3x = 5 - 2 = 3
x = 1

Step 3: substitute the result into the equation of Step 1:
y = x + 1 = 1 + 1 = 2

Result: x = 1, y = 2

Another way to do the same thing is add or subtract the equations to eliminate one of the varaibles, then solve for the other. Sometimes you need to scale one of the equations. In the example I gave, you can just subtract the 2nd from the 1st to eliminate x:

x + 2y = 5
-(x - y = -1)
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0 + 3y = 6 ==> y = 2