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Example 1
If $\dfrac{3y-t}{y+t}=5$, then y=?
- $t$
- $3t$
- $-2t$
- $-3t$
- $2t$
Solution
This example is about solving literal equations including several variables.
- Rewrite the given equation with rational expression on each side as follows
$\dfrac{3y-t}{y+t}=\dfrac{5}{1}$
- We now use the cross product to obtain
$(3y-t)\cdot 1 = (y+t)\cdot 5$
- Expand and group like terms
$3y-t=5y+5t$
$3y-5y=5t+t$
$-2y=6t$
- Solve for $y$
$y=-3t$
Answer D
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