ShmoopTube
Where Monty Python meets your 10th grade teacher.
Search Thousands of Shmoop Videos
Linear and Nonlinear Equations Videos 15 videos
FYI: cats don't like to get wet. Okay, so that fact won't be relevant every time you solve trig equations, but it happens to be this time.
Time to rewrite linear equations....ahem: linear equations. Tah-dah.
You can learn pretty much all there is to know about a linear equation by checking its relationship status. Just keep your fingers crossed that it...
ACT Math 2.5 Elementary Algebra 286 Views
Share It!
Description:
ACT Math Section: Elementary Algebra Drill 2, Problem 5. Use these two equations to solve for both x and y.
- Elementary Algebra / Linear equations
- Product Type / ACT Math
- Foreign Language / Arabic Subtitled
- Foreign Language / Korean Subtitled
- Foreign Language / Spanish Subtitled
- Foreign Language / Chinese Subtitled
- Algebra / Solve systems of equations
- Algebra / Solve systems of equations
- Algebra / Solve systems of equations
- Algebra / Solve systems of equations
- Elementary Algebra / Evaluation of algebraic expressions through substitution
Transcript
- 00:02
Here's your shmoop du jour:
- 00:05
Solve for x and y: 3x + 2y = 13 6x + y = 20
- 00:11
And here are the potential answers...
- 00:20
OK. Not much of a brain-squeezer.
- 00:23
Since y, stands alone in the bottom equation, let's solve for y.
Full Transcript
- 00:27
We get y equals 20 minus 6x.
- 00:30
Now we just substitute 20 minus 6x anywhere we see a y.
- 00:34
Ok so rewrite the above equation with that substitution and we have
- 00:37
3x plus 40 minus 12x equals 13
- 00:41
Simplify to get negative 9x equals 13 minus 40 or negative 9x equals negative 27; divide
- 00:48
both sides by negative 9 and we get x equals 3.
- 00:52
Phew. Great. Only A and B are possible answers.
- 00:55
Now just plug in 3 for x in the second equation
- 00:58
and we get 6 times 3 is 18... plus y... equals 20.
- 01:02
Now subtract 18 from both sides and we get y equals 2.
- 01:06
Here we go. So boom! The answer is B.
Related Videos
ACT Math: Plane Geometry Drill 3, Problem 1. What is the area of the trapezoid shape in the video?
ACT Math: Coordinate Geometry Drill 1, Problem 1. Which inequality is expressed by the number line?
ACT Math: Intermediate Algebra: Drill 3, Problem 1. Find the fifth number in the series.
You don't want to leave a bunch of unsolved rational equations sitting around.
Solving inequalities using blob fish? Yes, please!