When using the substitution method for a system of equations, one equation should be y = ... or x = ... (if both equations are not in this format you need to make one equation this way).
Once you have an equation in one of these formats, you take the equation and input it into the value of its correspondent of the other equation.
In this case you have y= 5-3x and 5x-4y=-3.
You should have 5x-4(5-3x)=-3.
Note how the first equation is substituted for the y value of the second equation.
Next solve. First distribute, 5x-20+12x=-3. Combine like terms. 17x-20=-3. Separate the variable and constants by adding 20 to both sides.
17x-20+20=-3+20 -> 17x=17. Divide both sides by 17 to get x = 1.
Now we need to find y. Go back to the first equation and input your x value into it and solve. y=5-3(1) -> y=5-3 -> y = 2
You can check your answer by inputting both values into the second equation and solving. 5(1)-4(2)=-3 -> 5-8=-3 -> -3=-3
The answer is (1,2)
