Math Prob 34?

Question

Solve the system:

xy = 8

x + y = 6

Answer 1

xy=8, so x =8/y, y can not be zero.

x + y = 6
(8/y) + y =6
8 + y^2 = 6y
y^2 -6y + 8 = 0
(y-4)(y-2)=0
y = +4 or y=+2
x=2, y=4; and x=4, y=2

Answer 2

You can do this in your head xy = 8
x + y = 6

It should be readily seen that the answers are 2 and 4

cause 2 x 4 + 8 AND 2 + 4 = 6

Answer 3

First: take either equation and solve for "x" or "y" ...let's take the first equation and solve for "y." Divide both sides by "x" and keep "y" on one side:

xy = 8 >
(xy)/x = 8/x
y = 8/x

Second: take 8/x and replace it with the "y" variable in the second equation. Get rid of the fraction: take the denominator and multiply it by everything:

x + 8/x = 6
x(x) + x(8/x) = x(6)
x^2 + 8 = 6x

Third: set the equation to equal "0" and factor. Take both sets to equal "0" and solve for "x" variables:

x^2 - 6x + 8 = 6x - 6x
x^2 - 6x + 8 = 0

(x - 4)(x - 2) = 0

x - 4 = 0
x - 4 + 4 = 0 + 4
x = 4

x - 2 = 0
x - 2 + 2 = 0 + 2
x = 2

x = 2, 4

Answer 4

when x=4,y=2 and when x=2,y=4

Answer 5

You will not do well in your exams if you ask for all your answers without thinking about the question. I have just ask my 9 year old and he answered very quickly 2,4. Always look for the factors of the answer when you have an xy equation

Answer 6

y=8/x

x+8/x=6

x^2-6x+8=0

x=4 or 2 substituing this in equation

y=4 or 2
the answer is

X is either 4 or 2
Y is either 4 or 2

Answer 7

4*2=8

4+2=6

The answer is 4 or 2

Answer 8

x^2-6x+8=0
(x-2)(x-4)=0

x-2=0
x1=2

x-4=0
x2=4

Answer 9

So, how's YOUR homework going?

Answer 10

4,2