CAHSEE Math 1.3 Mathematical Reasoning

CAHSEE Math Mathematical Reasoning: Drill 1 Problem 3. Which of the following is the correct order of steps?

AlgebraWord Problems
CAHSEE MathMathematical Reasoning
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Mathematical ReasoningAnalyzing problems

Transcript

00:25

and it throws in some curves and freebies as well.

00:29

Note that potential answer B asks about SUBTRACTING a half from both sides – well, since our

00:35

one-half on the left is already negative, we wouldn’t be able to cancel it out.

00:40

It would just be useless so we can eliminate option B right away.

00:43

Consider just the remaining 3 – and remember that the key goal in solving any of these

00:47

kinds of problems is to isolate x.

00:50

If we add a half to both sides – which is the first thing we do in the other potential

00:54

answers – the new equation looks like this:

00:57

1 over x equals 3 plus one-half.

01:01

So the next step is to just simplify 3 PLUS 1 half to be uh, yeah – 3 and a half.

01:08

Note that C has you subtracting a half as the second step here – and that’s just wrong –

01:13

we’ve ADDED a half to both sides; so you can cross out C.

01:17

So it gets down to D versus A.

01:21

A suggests taking the RECIPROCAL of the result whereas D asks us to take the OPPOSITE of the result.

01:28

The… opposite of the result? Not even sure what that would be. Sounds like someone who

01:32

just landed on our planet and is trying to fit in.

01:35

Taking the RECIPROCAL, however, makes sense.

01:37

Since we have 1 over x on the left side of the equation,

01:40

we can simply flip both sides to get x on the left…

01:44

…and one over 3 and a half on the right… which is 1 over 7 halves… or two-sevenths.

01:50

A it is.

01:51

As in… “Alien mathletes.”