If `x^2 - a = 14` and `x^2+a=16,` what is the value of `a` ?
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calendarEducator since 2012
write290 answers
starTop subject is Math
I edited your original question in response to Answer #2.
If you subtract the first equation from the second one, you get `2a=2,` so `a=1.`
Althought it wasn't asked for, you can go further and solve for `x,` and we find that both `+-sqrt(15)` work. Finally, we can check our solution:
`(+-sqrt(15))^2-1=14` and `(+-sqrt(15))^2+1=16,` so it works.
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calendarEducator since 2010
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It is given that x^2 - a = 14.
This equation has two variables x and a. x^2 - a can be equal to 14 for infinite number of sets of x and a. It is not possible to determine a unique solution for a from the given equation.
As the equation x^2 - a = 14 has 2 independent variables it is not possible to determine a unique solution for a.
x^2 -a - x^2 -a = 14 - 16
-2a = -2
a = 1
and
combine the problems:
x^2 -a - x^2 -a = 14 - 16
simplify
-2a = -2
divide by -2
a = 1
Sorry there is another equation x^2 + a = 16
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