Pre Algebra Homework help

Jenni376

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Joined
Jan 14, 2013
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1
I am trying to help my daughter with her homework and feel like this is a foreign language. Can someone help. Here is one of the problems. If you can tell me how to solve it, I can figure out the rest of the problems.

x
___
2 = 7 and also


-1
___
8 p = 3


:confused:
 
I am trying to help my daughter with her homework and feel like this is a foreign language. Can someone help. Here is one of the problems. If you can tell me how to solve it, I can figure out the rest of the problems.

x
___
2 = 7 and also


-1
___
8 p = 3


:confused:
It greatly helps if you show division using /.

Is the first problem

\(\displaystyle x/2 = \dfrac{x}{2} = 7 \implies \frac{1}{2}x = 7.\)

The rule is to multiply both sides of the equation by the multiplicative inverse of the unknown's coefficient.

What does that mean in English?

\(\displaystyle 3u = 21.\) The multiplicative inverse of 3 is 1/3

\(\displaystyle \frac{1}{3} * 3u = \frac{1}{3} * 21 \implies\)

\(\displaystyle \dfrac{3u}{u} = \dfrac{21}{3} \implies\)

\(\displaystyle u = 7.\)

But our question involves a fractional coefficient. Same process. But what is the multiplicative inverse of a fraction. Just flip the fraction upside down.

\(\displaystyle x/2 = \dfrac{x}{2} = 7 \implies \frac{1}{2}x = 7.\) When I flip 1/2 upside down, I get 2/1 = 2.

\(\displaystyle x/2 = \frac{1}{2}x = 7 \implies 2 * \frac{1}{2}x = 2 * 7 \implies x = 14.\)

Is that clear or do you have questions. if you are OK here, let's go on to problem 2
 
It greatly helps if you show division using /.

Is the first problem

\(\displaystyle x/2 = \dfrac{x}{2} = 7 \implies \frac{1}{2}x = 7.\)

The rule is to multiply both sides of the equation by the multiplicative inverse of the unknown's coefficient.

What does that mean in English?

\(\displaystyle 3u = 21.\) The multiplicative inverse of 3 is 1/3

\(\displaystyle \frac{1}{3} * 3u = \frac{1}{3} * 21 \implies\)

\(\displaystyle \dfrac{3u}{u} = \dfrac{21}{3} \implies\)

\(\displaystyle u = 7.\)

But our question involves a fractional coefficient. Same process. But what is the multiplicative inverse of a fraction. Just flip the fraction upside down.

\(\displaystyle x/2 = \dfrac{x}{2} = 7 \implies \frac{1}{2}x = 7.\) When I flip 1/2 upside down, I get 2/1 = 2.

\(\displaystyle x/2 = \frac{1}{2}x = 7 \implies 2 * \frac{1}{2}x = 2 * 7 \implies x = 14.\)

Is that clear or do you have questions. if you are OK here, let's go on to problem 2
You know that there is an easier way to do that: _____ divided by 2 =7? easy! 14!
 
JeffM is showing the OP the general technique for solving equations of this type. While it may be easy to "eyeball" the solution for many problems, it becomes helpful to know the algebraic method for solving when the solution isn't so readily apparent.
 
You know that there is an easier way to do that: _____ divided by 2 =7? easy! 14!

Lilibeth,

Can you please show us the easy way to do the second problem?

Find p when


\(\displaystyle \dfrac{-1}{8p} \ = \ 3\)
 
An accurate algebra answer needs step by step refinement of the equation. Sometimes we get trap in such equations, then we need help from our seniors.. like online sites are also helpful now a days in the internet provide online help to the students.
 
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