Question

explain how to solve for y

https://media.glynlyon.com/g_alg01_2012/10/327.gif

these are the awsers they gave



y = 13

y = 15

y = 31

y = 33

Answer 1

DD: I'd be glad to help. However, I'll want to hear about what you've already done before jumping in with explanations.

You are combining two fractions with different denominators here. What have you done in the past to make that possible?

How would you add 1/3 to 1/7?

What does "LCD' mean to you?

Answer 2

find the lcd of the bottom two numbers ??

Answer 3

If you know enough to ask that, then you're on the right track.

Add: 1/3 + 1/7

Answer 4

which is like this

7-14-21-28

3-6-9-12-15-18-21

Answer 5

21

Answer 6

that is the correct LCD for the problem 1/3 + 1/7, but you haven't yet finished this addition. Please finish it.

Answer 7

10/21

Answer 8

That's an interesting way to find the LCD. Yes, your LCD is 21. Nice going. How are y ou doing at adding those 2 fractions together?

Answer 9

Great.
Combine: 3/7 - 2/5

Answer 10

is that a subtracting symbol?

Answer 11

Yes, DD, I'm asking you to subtract 2/5 from 3/7.

Answer 12

1/35

Answer 13

???? @mathmale

Answer 14

I'll be right with you. 35 is the correct LCD. Would you please describe in words what you did to obtain that 1 in the numerator?

Answer 15

this is dd dad what is the answere to it please im trying to help with this. i have an answer and want to know if im doing it right

Answer 16

i got 13

Answer 17

@robtobey

Answer 18

DD: It's important that you understand the steps of evaluating 3/7 - 2/5 well enough to explain the process in words. You do have the correct answer, however, so I'm going to let you off the hook and go back to your original question.

Answer 19

Combine as indicated:

15 10
------- - ------
y+11 y+3

DD and DD's Dad: Please identify the LCD.

Answer 20

Cross multiply and then solve for y.
Refer to the Mathematica attachment.

Answer 21

That "cross-multiply" suggestion would be a good one, but does not free you from identifying and using the LCD.

DD: Please identify the LCD in this problem.

Answer 22

is it 13 ?

Answer 23

Yes.

Answer 24

No. Please refer to your original problem statement:


https://media.glynlyon.com/g_alg01_2012/10/327.gif

The LCD is the product *(y+11)(y+3).

Please respond in some way, DD: Can you agree with this? Or not? Any questions?

Answer 25

the lcd is 48 if you plug 13 in

Answer 26

DD: I see you are trying to decide which of the four possible answers is the correct one. If you want to "solve" this problem in that way, you can, but doing it algebraically (which would include finding the LCD) would be far more beneficial to you in the long run. The LCD I identified for you above is correct. Your move. Move on to another problem or learn how to use those LCDs in the solution of problems like this one.

Answer 27

@mathmale

You will probably find that the following video goes against the grain of today's
conventional math educators.

Conrad Wolfram: Teaching kids real math with computers

http://www.ted.com/talks/conrad_wolfram_teaching_kids_real_math_with_computers.html

As one who graduated in the lower 1/3 of his college class, with the use of the Mathematica computer program, I am answering questions posted on this math site that no one else can or does not want to take the time to answer.

Answer 28

I appreciate your contributing thoughtful alternative approaches. I'm deaf, and the video is not captioned, so am unable to get much from it.

I respect and admire you for answering or approaching questions that no one else can or wants to take the time to answer.

What are you doing now? Working? Hope it's satisfying for you.

Answer 29

I will be 80 years old next August and retired for some years.
Participating in openstudy.com as a math hobbyist.
My grammar school graduation picture was taken in 1946.
Was a main frame computer programmer for the Lockheed Missile and Space Co
for 12 years.