# Squares and routes

• Jan 8th 2010, 12:05 PM
Mukilab
Squares and routes
If I want to cancel a square a.k.a 4^2 do I multiply or add it to the square route of said number (4 here)
• Jan 8th 2010, 12:10 PM
mr fantastic
Quote:

Originally Posted by Mukilab
If I want to cancel a square a.k.a 4^2 do I multiply or add it to the square route of said number (4 here)

This small isolated part of what is clearly a larger question makes no sense without more context.
• Jan 8th 2010, 12:14 PM
pickslides
You don't add or multiply the square root, you 'take' the square root.

I.e you may have $x^2 = 81$ and you want to find $x$

which is the same as

$x^2 = 9^2$

now you can see you can take the square root of both sides.

$\sqrt{x^2} = \sqrt{9^2}$

which in turns yields

$x = 9$

As square and square root are opposites.

Now go ahead and change the world!
• Jan 8th 2010, 12:15 PM
Mukilab
Quote:

Originally Posted by mr fantastic
This small isolated part of what is clearly a larger question makes no sense without more context.

No, I just need to know this for a simultaneous equation. If I need to cancel out a 4^2 do I use multiply by \sqrt{4} or add by \sqrt{4}
• Jan 8th 2010, 12:27 PM
pickslides
I am starting to agree with this comment

Quote:

Originally Posted by mr fantastic
This small isolated part of what is clearly a larger question makes no sense without more context.

• Jan 8th 2010, 12:35 PM
Mukilab
Quote:

Originally Posted by pickslides
I am starting to agree with this comment

....

By eliminating y find solutions to the simultaneous equations

x^2+y^2=25
y=2x-2
• Jan 8th 2010, 12:42 PM
mr fantastic
Quote:

Originally Posted by Mukilab
....

By eliminating y find solutions to the simultaneous equations

x^2+y^2=25
y=2x-2

Substitute y=2x-2 into x^2+y^2=25, expand, simplify and solve the quadratic for x. Then substitute the values of x into y=2x-2 to get y.