SOLUTION: Solve the following equation for x and y: (2)^2+x +(3)^3+y=275 (2)^3+x +(3)^2+y=145

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Question 1035244: Solve the following equation for x and y:
(2)^2+x +(3)^3+y=275
(2)^3+x +(3)^2+y=145

Answer by ikleyn(52788) About Me  (Show Source):
You can put this solution on YOUR website!
.
Solve the following equation for x and y:
(2)^2+x +(3)^3+y=275
(2)^3+x +(3)^2+y=145
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Since you do not use parentheses properly, there are several ways to read your system.
Your writing is ambiguous. To avoid ambiguity, use parentheses.

Is THIS modification what you want?

2%5E%282%2Bx%29+%2B++3%5E%283%2By%29 = 275,     (1)
2%5E%283%2Bx%29+%2B++3%5E%282%2By%29 = 145.     (2)


Below is the solution of this system.


Since 2%5E%282%2Bx%29 = 4%2A2%5Ex, 3%5E%283%2By%29 = 27%2A3%5Ex, 2%5E%283%2Bx%29 = 8%2A2%5Ex, 3%5E%282%2By%29 = 9%2A3%5Ex, you can rewrite the system (1), (2) in the form

4%2A2%5Ex + 27%2A3%5Ey = 275,      (1')
8%2A2%5Ex + 9%2A3%5Ey = 145.       (2')

This system is still non-linear.
The way to solve it is to introduce new variables u = 2%5Ex and v = 3%5Ey.
Then the system (1'), (2') takes the form

4u + 27v = 275,         (3)
8u +  9v = 145.         (4)

The system (3), (4) is just a linear, and we can easily solve it.
I will use the Elimination method. Multiply equation (3) by 2 (both sides). You will get

8u + 54v = 550,         (3')
8u +  9v = 145.         (4')

Now, distract (3') from (4'). You will get

54v - 9v = 550 - 145  --->  45v = 405  --->  v = 405%2F45 = 9.

Now recall that v = 3%5Ey,  or  9 = 3%5Ey.  Hence,  y = 2,  and one unknown is just found.

Next, from (3)  u = %28275+-+27v%29%2F4 = %28275-27%2A9%29%2F4 = 32%2F4 = 8.

Again, recall that  u = 2%5Ex,  or 8 = 2%5Ex.  Hence,  x = 3.

The problem is solved.

Answer.  x = 3,  y = 2.

You can check that the solution is correct.