If y varies directly with x, write an equation for the direct variation. If y=14 when x=8, find y when x=12. Is the answer x=21y?

Question

If y varies directly with x, write an equation for the direct variation.  If y=14 when x=8, find y when x=12.  Is the answer x=21y?

anonymous · Answer

no

anonymous · Answer

the questions wants you to find y and they dont want an expression

anonymous · Answer

@triciaal Please help!

anonymous · Answer

@mathmale Am I right?

anonymous · Answer

You're very close. For our first relation, we have x=8, y=14. You've rightly multiplied by a factor of 1.5 to get 21, we have x=12 and y=21. Not x=21y.

anonymous · Answer

umm...the factor is 1.75 not 1.5

anonymous · Answer

since its direct relation, there will be a scale factor so your first step is to find that

anonymous · Answer

$$y=kx$$
$$14=k8$$

anonymous · Answer

So what you're saying is $\frac{12}{8}=1.75$? You might want to put that in your calculator.

anonymous · Answer

that is not what i said

anonymous · Answer

if you read the question carefully, you'll find that when x=8, y =14. therefore, 14/8 = 1.75

triciaal · Answer

|dw:1449465225978:dw|