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Systems of Equations Videos 73 videos
CAHSEE Algebra I: Drill 1, Problem 1. What are some of the properties used to solve this equation?
Algebra I Drill 2, Problem 3. Which of the following is the same as the expression?
CAHSEE Math 3.3 Algebra I 195 Views
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Description:
Algebra I Drill 3 Problem 3. What is the x-intercept of the equation?
Transcript
- 00:02
Here’s your shmoop du jour...
- 00:04
What is the x-intercept of the equation 2x - 7y = 14?
- 00:09
And here are the potential answers…
- 00:15
So… what’s an intercept?
- 00:17
An intercept – in algebra – is the part of the line that crosses the primary axis.
Full Transcript
- 00:22
That is, the x intercept is where the line crosses the x axis like… here… and the
- 00:28
y axis is where it crosses… yes, shocker… the Y axis… here.
- 00:34
So to solve the problem, we have to figure out what y is when x equals zero, and vice versa.
- 00:40
We can just plug in zero for x in the equation, to get 2 times zero, which is zero…
- 00:45
minus 7y equals 14.
- 00:48
Divide both sides by negative 7 and we get y equals negative 2.
- 00:52
Yeah, we didn’t HAVE to do that part to answer the question but it can’t hurt to
- 00:56
know for future reference.
- 00:57
Now we can plug in 0 for y to get 2x minus 7 times zero, which is 0, equals 14…
- 01:06
…so 2x equals 14. Now divide both sides by 2 and x equals 7.
- 01:13
The line crosses the x axis when x equals 7…
- 01:16
…and so our answer is D. Done.
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