ligia587
which is expression is equivalent to
Delete
Share
This Question is Closed
ligia587
Best Response
You've already chosen the best response.
0
if \[\sqrt{x-a}=b, x>a \]
ligia587
Best Response
You've already chosen the best response.
0
which expression is equivalent to x?
\[b^{2}-a \]
ligia587
Best Response
You've already chosen the best response.
0
\[b-a\]
ligia587
Best Response
You've already chosen the best response.
0
b+a
ligia587
Best Response
You've already chosen the best response.
0
or b^2+a
kirbykirby
Best Response
You've already chosen the best response.
1
\[\sqrt{x-a}=b\]=>\[x-a=b^2\]=>\[x=b^2+a\]
kirbykirby
Best Response
You've already chosen the best response.
1
When solving with radicals, square both sides because \[(\sqrt{x})^2=x\]
kirbykirby
Best Response
You've already chosen the best response.
1
It will just get rid of it :)!!
ligia587
Best Response
You've already chosen the best response.
0
so b^2+ a is the answer?
kirbykirby
Best Response
You've already chosen the best response.
1
yes
ligia587
Best Response
You've already chosen the best response.
0
how did you know x=> ?
kirbykirby
Best Response
You've already chosen the best response.
1
Did you understand the first step? that x-a = b^2 ?
ligia587
Best Response
You've already chosen the best response.
0
no i dont
ligia587
Best Response
You've already chosen the best response.
0
|dw:1358391793350:dw|
kirbykirby
Best Response
You've already chosen the best response.
1
Ok. Do you understand why \[(\sqrt{x})^2=x\]?
kirbykirby
Best Response
You've already chosen the best response.
1
The "x > a" is just imposing a restriction value on your x. You don't need to use it to solve for x
ligia587
Best Response
You've already chosen the best response.
0
where did you get the square
from?
kirbykirby
Best Response
You've already chosen the best response.
1
It's what you need to do in order to solve the equation. It's similar to like when you have an equation like:
\[2x-4=10\]\[2x=10+4\]\[2x=14\]\[\frac{2x}{2}=\frac{14}{2}\]\[x=7\]
You could argue "how did you get the divided by 2 part?" Well it's similar to your situation. You introduce this exponent to get rid of your square root, just like you introduced a divided by 2 up here^ to isolate your x
ligia587
Best Response
You've already chosen the best response.
0
ohh ok
ligia587
Best Response
You've already chosen the best response.
0
thanks so much :)
kirbykirby
Best Response
You've already chosen the best response.
1
No problem :)
ligia587
Best Response
You've already chosen the best response.
0
can you help me with another problem?
kirbykirby
Best Response
You've already chosen the best response.
1
SUre
kirbykirby
Best Response
You've already chosen the best response.
1
@ligia587
ligia587
Best Response
You've already chosen the best response.
0
yea?
ligia587
Best Response
You've already chosen the best response.
0
i thought you left
kirbykirby
Best Response
You've already chosen the best response.
1
I can help your with your question if you need
kirbykirby
Best Response
You've already chosen the best response.
1
you*