ShmoopTube
Where Monty Python meets your 10th grade teacher.
Search Thousands of Shmoop Videos
ACT Math Videos 161 videos
ACT Math: Plane Geometry Drill 3, Problem 1. What is the area of the trapezoid shape in the video?
ACT Math Intermediate Algebra Drill 1, Problem 1. What is the product of (a – 3)2?
ACT Math Intermediate Algebra Drill 1, Problem 4. Solve for x based on the equation.
ACT Math 1.5 Elementary Algebra 264 Views
Share It!
Description:
Math Elementary Algebra: Drill 1, Problem 5. Solve for a using substitution.
- Elementary Algebra / Substitution
- Elementary Algebra / Linear equations
- Product Type / ACT Math
- Foreign Language / Arabic Subtitled
- Foreign Language / Spanish Subtitled
- Foreign Language / Korean Subtitled
- Foreign Language / Chinese Subtitled
- Elementary Algebra / Evaluation of algebraic expressions through substitution
Transcript
- 00:03
Here's your shmoop de jour
- 00:06
Solve for a using substitution: 4a = b - 8
- 00:10
a + b = 18
- 00:13
And here are the potential answers...
- 00:17
OK fun problem.
Full Transcript
- 00:19
It's another one of those problems that wants us to put our super-duper substitution skills
- 00:25
to work.
- 00:28
We want to get either a or b alone. Like what is a simply or what is b simply
- 00:36
In the first equation, b's already by itself...
- 00:39
...so we can just add 8 to both sides to get b = 4a + 8.
- 00:48
Plugging that into the other equation in place of b, we get a + 4a + 8 = 18...
- 00:54
...and when we slap our a terms together and subtract 8 from each side...
- 00:58
...we're left with 5a = 10. Divide both sides by 5, and a = 2.
- 01:04
Our answer is B.
- 01:05
As in, "Binomial Man."
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!