How to do this maths question?

Question

How do you do x^2 + y^2 = 9 , solving for x ?

And also

(x/a) - 1 = (x/b)+2
again solve for x

Thanks ^^

Answer 1

Always try to get what you're solving for on one side. So, for number 1,

x^2 = 9 - y^2
Then take the square root of both sides.

For the second one, get ALL terms with x on one side.
(x/a) - (x/b) = 2 +1
Then factor out the x's:
x(1/a - 1/b) = 3

I'll let you do the rest =)

Answer 2

Rearrange x^2 + y^2 = 9 transposing y^2 to the other side making it x^2 = 9 - y^2.
Taking the squared of x you squareroot 9 - y^2 so making it
x = squareroot of 9 - y^2 to take away the squared of x.

2nd Eq.
x/a - 1 = x/b + 2 Transpose -1 to the other side making it
x/a = x/b +2 +1. Transpose x/b to the other side and take away x changing it to one making it x(1/a - 1/b) = 3.
Then getting the LCD making it x(b - a/ab) = 3. Cross multiply making it x = 3(ab)/b-a.
So your equation will be x = 3(ab)/b-a

Answer 3

#1. seperate variables, so
x^2 = 9-y^2
take square roots
x= +/- sqrt(9-y^2)

#2 collect x terms on one side
(x/a) - (x/b) = 2+1 = 3
Combine fractions
(b-a) x /(ab) = 3
Isolate x
x= 3 ab / (b-a)

Answer 4

x^2 + y^2 = 9
x^2 = 9 - y^2 --get terms involving "x" on one side of eqn
x = sqrt(9 - y^2) ---take square root of both sides

x/a - 1 = x/b + 2
x/a - x/b = 1 + 2 --- get terms involving "x" on one side of eqn
x(1/a - 1/b) = 3 ---factor out an "x", simplify right side
x = 3 / (1/a - 1/b) --- divide both sides by 1/a - 1/b.

Answer 5

To solve for x, you need to make it look like x=somethingsomething

x^2=9-y^2 (subtract y^2 from both sides)
x=sqrt(9-y^2) (take square root on both sides)

For the next problem, x is on both sides of the equation. We only want it on one side, so we can get x=something. I always like the left side. You can treat a and b like numbers.

(x/a)-1=(x/b)+2
(x/a)=(x/b)+3 (add 1 to both sides)
(x/a)-(x/b)=3 (subtract (x/b) from both sides)
(b*x/a)-x=3b (multiply by b on both sides)
(b*x)-(a*x)=3ab (multiply by a on both sides)
x(b-a)=3ab (factor b-a from x)
x=3ab/(b-a) (divide by (b-a) on both sides)

And that's it!! Hope this helps.

Answer 6

re-arrange the 2nd eq.

x/a - x/b = 2+1, x(1/a-1/b) = 3 , x = 3ab/(b-a)