9. Direct Variation
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What is the form of a direct variation equation?
Equation: y= 78x
Solution: x=112
Functions where y varies directly with x — direct variation equations — follow a specific format.
y= kx
In this form, k≠0.
By substituting the given values for x and y into the equation, we can determine the constant of variation, k.
Now that we have the constant of variation, we can write the function. y= 7/8x With this equation, we can find any value of x or y when we are given the other. In this case, we are looking for x when y=14.
y= 14
a/c* b = a* b/c
LHS * 8=RHS* 8
Multiply
Rearrange equation
For the equation y= 78x, when y=14, the value of x is 112.