Anyway I got x = 3a/(b – 3). Theres no definite number for x because you have two unknown variables. You can’t solve for two unknowns with only one equation.

I wonder if it signifies anything that all of us have different answers. Oh well, here’s mine.

Work:

x + a = (b/3)x (start)

x – x(b/3) = -a (-a from both sides and -x(b/3) from both sides)

-x/b + (x/3) = a/b (divide both sides by -b)

x(-1/b + 1/3) = a/b (factor out x)

x = a/(b(-1/b + 1/3)) (divide both sides by (-1/b + 1/3) )

x = a/(-b/b + b/3) (factor in b)

x = a/(-1 + b/3) (Simplify -b/b = -1)

x = a/(-3/3 + b/3) (Rewrite -1 as -3/3)

x = a/((-3 +b)/3) (Combine terms with common denominator)

x = 3a/(b – 3) (Simplify the fraction)

I believe that is what the answer should be. It fits the pattern that b cannot be equal to 3 otherwise you would have a divide by zero which is impossible.

Answer two and four from above are solvable if b = 3 which leads me to believe that they are not correct.

Answer three does fit the trend however, if he simplified

(1/x) = (b/3a) – (1/a) (Rewrite 1/a as 3/3a (multiply 1/a by 3/3))

(1/x) = (b/3a) – (3/3a) (subtract terms)

(1/x) = (b-3/3a) (take the inverse)

x = (b – 3)/3a (my answer)

In my experience, you always must simply first before doing any larger operations such as an inverse.

Anyway, thats my explanation. Good luck to you. I’m an Computer Science major and I’ve taken four levels of Calculus (not that I remember a whole lot of it) but I’d say my alegbra is okay for the most part. 😛

Best of luck to you with your calc.

x+a=(b/3)x

Open the brackets: x+a=bx/3

Multiply 3 on both sides: 3(x+a)=bx

Open the brackets again: 3x+3a=bx

Group and factorise out X: x(3-b)=-3a

Divide by (3-b) throughout: x=-(3-b)/3a

Simplify: x= (b-3)/3a (ans)

1 + (a/x) = (b/3)

(a/x) = (b/3) – 1

(1/x) = (b/3a) – (1/a)

x = (3a/b) – a

=>> x(3-b) = -3a =>> x= -3a/(3-b) = 3a/(b-3)

x+a=bx/3

3(x+a)=bx

3x+3a=bx

x(3-b)+3a=0

x(3-b)=-3a

x=-(3-b)/3a