Solve for x in terms of a and b: 1a+b+x=1a+1b+1x\frac{1}{a+b+x}=\frac{1}{a}+\frac{1}{b}+\frac{1}{x}(Where a, b, x ≠ 0 and a + b + x ≠ 0)

Answer: x=−aorx=−bx = -a \quad \text{or} \quad x = -b

Step-by-step solution

Step 1: Rearrange the equation

To begin solving for xx, we first rearrange the equation by moving the term 1x\frac{1}{x} from the right side to the left side. This groups terms involving xx together.

Step 2: Combine fractions on both sides

Next, we combine the fractions on both sides of the equation by finding a common denominator for each side. On the left, the common denominator is x(a+b+x), and on the right, it is abab.

Step 3: Simplify the equation

We simplify the numerator on the left side: x−(a+b+x)=x−a−b−x=−a−bx - (a+b+x) = x - a - b - x = -a - b. This gives us −(a+b)x(a+b+x)=a+bab\frac{-(a+b)}{x(a+b+x)} = \frac{a+b}{ab}.

Step 4: Cross-multiply and solve for x

Since a+b≠0a+b \neq 0 (otherwise the original equation would be undefined), we can divide both sides by (a+b). This simplifies the equation to −1x(a+b+x)=1ab\frac{-1}{x(a+b+x)} = \frac{1}{ab}. Then, we cross-multiply to get −ab=x(a+b+x)-ab = x(a+b+x).

Step 5: Form a quadratic equation

We expand the right side of the equation: x(a+b+x)=x2+(a+b)xx(a+b+x) = x^2 + (a+b)x. Moving −ab-ab to the right side, we get x2+(a+b)x+ab=0x^2 + (a+b)x + ab = 0. This is a quadratic equation in terms of xx.

Step 6: Factor the quadratic equation

We can factor the quadratic equation x2+(a+b)x+ab=0x^2 + (a+b)x + ab = 0 into (x+a)(x+b)=0(x+a)(x+b) = 0. This is because a×b=aba \times b = ab and a+b=a+ba + b = a+b.

Step 7: Solve for x

From the factored form (x+a)(x+b)=0(x+a)(x+b) = 0, we set each factor equal to zero to find the possible values for xx. This gives us x+a=0  ⟹  x=−ax+a=0 \implies x=-a or x+b=0  ⟹  x=−bx+b=0 \implies x=-b.

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