A few days ago
alex_berish14

need help with algebraic relationships please!!?

ok

The sum of two numbers is 9, and their product is 12. I need to find the sum of their reciprocals.

im pretty sure this problem involves fractions/decimals

you dont have to answer it for me (although that would help)

but the basic procedure for getting the answer would be awesome… thanks guys.

Top 2 Answers
A few days ago
?

Favorite Answer

Let the two numbers x and y

so there would be two equations:

1) x + y = 9

2) xy = 12

then in the first equation, isolate y

y = 9-x

then sub y=9-x in the second equation

x(9-x) = 12

then expand it

9x – x^2 = 12

if you rearrange it, you will get

-(x^2-9x-12)=0

After that you can use the quadratic formula to solve it!

I don’t like fractions! 🙁

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A few days ago
drkdepolo
x + y = 9

x * y = 12

So, x = 12/y. Put this into the other equation for x, getting 12/y + y = 9. Then solve for y.

I don’t know if you need this part as well, but the reciprocal is 1 over the number, so 1/y + 1/x.

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