WorksheetsSolving Systems by Substitution Review Short
Total questions: 5
Worksheet time: 3mins
Before you start, GET OUT PAPER AND PENCIL!
Consider the system of equations
2x−3y=−11
2x+y=9
Which equation has the LEAST number of steps to solve for either x or y?
2x-3y=-11
2x+y=9
Hey you, yeah you, the one without the paper and pencil...GET IT OUT NOW!
If I solve the second equation (2x+y=9) for y, what is the result?
2x=3y-11
2x=9-y
y=9-2x
x=18+2y
Now the system of equations is
2x−3y=−11
y=9−2x
What is the result of plugging the second equation in for y in the first equation?
2x-3(9-2x)=-11
2x+(9-2x)=9
2(9-2x)-3y=-11
2(9-2x)+y=9
Solve the equation for x:
2x−3(9−2x)=−11
x= (a)
This was our original system
2x−3y=−11 2x+y=9
We solved the second equation for y to get the system
2x−3y=−11, y=9−2x
We plug the second equation into the first and solve to get x=2.
Now, plug x=2 into any equation to solve for y.
y= (a)
