SOLUTION: 1. If x + y = 17 and x^2 + y^2 = 167, what is the value of 3xy? 2. If x + y = 13 and xy = 17, what is the value of 2(x^2+y^2)? 3. If r^2 + s^2 = 18, and r + s = 5, what is th

Algebra ->  Complex Numbers Imaginary Numbers Solvers and Lesson -> SOLUTION: 1. If x + y = 17 and x^2 + y^2 = 167, what is the value of 3xy? 2. If x + y = 13 and xy = 17, what is the value of 2(x^2+y^2)? 3. If r^2 + s^2 = 18, and r + s = 5, what is th      Log On


   

Question 1168764: 1. If x + y = 17 and x^2 + y^2 = 167, what is the value of 3xy?
2. If x + y = 13 and xy = 17, what is the value of 2(x^2+y^2)?
3. If r^2 + s^2 = 18, and r + s = 5, what is the value of 4rs?
4. If x + y = 17 and x^2 + y^2 = 167, what is the value of 3xy?

Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39618) About Me  (Show Source):
You can put this solution on YOUR website!
%28x%2By%29%5E2=17%5E2
x%5E2%2By%5E2%2B2xy=289
167%2B2xy=289
xy=61
3%2Axy=%283%29%2861%29


----
----
What about #2 and #3?

Use #1, done here already, as a guide. Think! #1 and #3 are similar.





---

#2, just a start,
%28x%2By%29%5E2=169
x%5E2%2By%5E2%2B2xy=169
substitute using the other given equation,...
...

Answer by ikleyn(52797) About Me  (Show Source):
You can put this solution on YOUR website!
.
1. If x + y = 17 and x^2 + y^2 = 167, what is the value of 3xy?
2. If x + y = 13 and xy = 17, what is the value of 2(x^2+y^2)?
3. If r^2 + s^2 = 18, and r + s = 5, what is the value of 4rs?
4. If x + y = 17 and x^2 + y^2 = 167, what is the value of 3xy?
~~~~~~~~~~~~~~~~~~~


Notice that   #4  is identical to   #1,

so I do not understand for what reason you request two identical problems in one post.


I only can suggest that you do not read what you post,  at all.


If you have another explanation,  feel free to disprove my suggestion . . .