Question

One number is 7 more than another. The difference between their squares is 161. What are the numbers????

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Answer 1

Selected answers to common questions:
Mixture problems.

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Answer 2

take help from these

Answer 3

THAT IS LONG.

Answer 4

x^2-y^2=161
x+7=y
x^2-(x+7)^2-161=0
-14x-210=0
x=-15

Answer 5

i know saifoo but it will help her

Answer 6

and y = -8

Answer 7

should i put 8,15 or -8,-15

Answer 8

both'll work

Answer 9

but go ahead for the positive I guess

Answer 10

Thank you guys so much! I have a B average in my class but we just hit "applications of quadratic equations" and Im not doing well with it. Any suggestions?

Answer 11

@j-free give a medal it took me 4 mins to write these all!!!!!!!!!

Answer 12

\[(x+7)^{2}-x ^{2}=161\]
\[x ^{2}+14x+49-x ^{2}=161\]
\[14x=161-49=112\]
\[x=112/14=8\]

Answer 13

Application of quadratic equations? Like this question here? What is it that you have more trouble with? is it writing down the situation mathematically or when trying to solve it?

Answer 14

Changing the word problems into equation. Setting it up.

Answer 15

In a case like this where you have 2 different unkown values, pick one and associate it to x.
Then, find the relation between x and the second unknown and that's one of your equations which you'll probably be using to substitute in the second.
Next, for the second equation, that's usually the question (like here, x^2-y^2=161).

It's not really easy to give you advice regarding this, it's more something that comes with practice I think. If anybody has got good tricks to try to improve this, please let me know as well, it's always useful

Answer 16

thank you for you help again though! I definitely have some practicing on these to do.