If y=15 when x=5, find y when x=7, given that y varies directly with x.

when x = 7, y = 21

Step-by-step explanation:

This is about direct variation. If y varies directly with x, then there is a constant  factor of variation, k. The constant of variation can be found by ʸ⁄ₓ

k = ʸ⁄ₓ

k = ¹⁵⁄₅ = 3

Now that we have found k, we simply multiply x by it to find y (this is because y is directly proportional to x). We plug in our x = 7 to find y at this point.

y = 3x

y = 3(7)

y = 21

answer:   expression= p+p*d%

price reduction + sale price = $625

sale price: $p+$p*d%

where d% is the percentage of discount

step-by-step explanation:

original price = p

price went down by $150 price reduction $p*d%

sale price= $ 475

therefore the price before sale is: $625

and the expression that shows the price before sale is: p+p*d%

a reflection across the x axis and a 90 degree rotation left and right.