Finding the value of X

[BoomSchtick]

I need to find the value of X in the following equations:

5x-2y=8
x-5y=-3

The options are either -2, -1, 0, 1, 2

I know that I can use the options above and one at a time plug them in for X and solve for Y, but that takes a long time. I know there must be a way to figure it out algebraically, but have not been able to find how to do it.

The answer is -1 BTW...

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Also on this find X problem, I think I know the answer, but want to verify if I'm right:

7(Sqrt of x) + 3 = 4(Sqrt of x) - 9

The options are 4, 2, -2, -3, No Real Number Solution

4 and 2 are clearly not the answer because they do not come close to equaling each other when put in place of X. As far as I know, I can't take the square root of a negative, so the answer must be No Real Number Solution.

Does that sound right?

 

[Deleted member 4993]

I need to find the value of X in the following equations:

5x-2y=8
x-5y=-3

The options are either -2, -1, 0, 1, 2

I know that I can use the options above and one at a time plug them in for X and solve for Y, but that takes a long time. I know there must be a way to figure it out algebraically, but have not been able to find how to do it.

The answer is -1 BTW...

________________________________________________________________________
Also on this find X problem, I think I know the answer, but want to verify if I'm right:

7(Sqrt of x) + 3 = 4(Sqrt of x) - 9

The options are 4, 2, -2, -3, No Real Number Solution

4 and 2 are clearly not the answer because they do not come close to equaling each other when put in place of X. As far as I know, I can't take the square root of a negative, so the answer must be No Real Number Solution.

Does that sound right?

for a quick referesher (with example problem solved and explained ) - go to:

http://www.purplemath.com/modules/systlin4.htm

 

[Deleted member 4993]

Also on this find X problem, I think I know the answer, but want to verify if I'm right:

7(Sqrt of x) + 3 = 4(Sqrt of x) - 9

The options are 4, 2, -2, -3, No Real Number Solution

4 and 2 are clearly not the answer because they do not come close to equaling each other when put in place of X. As far as I know, I can't take the square root of a negative, so the answer must be No Real Number Solution.

Does that sound right? <<< Yes

\(\displaystyle 7\sqrt{x} + 3 = 4\sqrt{x} - 9\)

\(\displaystyle 3\sqrt{x} = - 12\)

\(\displaystyle \sqrt{x} = - 4\)

\(\displaystyle x = 16\)

applying this answer to given equation we get:

\(\displaystyle 7\sqrt{16} + 3 = 4\sqrt{16} - 9\)

\(\displaystyle 31 = 7\)...............doesn't satisfy - hence no solution in real domain

 

[Denis]

I need to find the value of X in the following equations:
5x-2y=8
x-5y=-3

Boomer, that's pretty basic stuff...are you a student or learning on your own ?

 

[BoomSchtick]

I need to find the value of X in the following equations:
5x-2y=8
x-5y=-3

Boomer, that's pretty basic stuff...are you a student or learning on your own ?

I'm a student, but it is all online and self paced, so I'm basically self teaching.

 

[BoomSchtick]

Also on this find X problem, I think I know the answer, but want to verify if I'm right:

7(Sqrt of x) + 3 = 4(Sqrt of x) - 9

The options are 4, 2, -2, -3, No Real Number Solution

4 and 2 are clearly not the answer because they do not come close to equaling each other when put in place of X. As far as I know, I can't take the square root of a negative, so the answer must be No Real Number Solution.

Does that sound right? <<< Yes

\(\displaystyle 7\sqrt{x} + 3 = 4\sqrt{x} - 9\)

\(\displaystyle 3\sqrt{x} = - 12\)

\(\displaystyle \sqrt{x} = - 4\)

\(\displaystyle x = 16\)

applying this answer to given equation we get:

\(\displaystyle 7\sqrt{16} + 3 = 4\sqrt{16} - 9\)

\(\displaystyle 31 = 7\)...............doesn't satisfy - hence no solution in real domain

I like your way better!