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3 years ago

If the value of y varies directly with x and y= -1 when x=3, find y if x=9

Mathematics

1 answer:

Zolol [24]3 years ago

4 0

y = - 3

Since y varies directly as x then

y = kx ← ( k is the constant of variation )

to find k use y = - 1 when x = 3

k = $\frac{y}{x}$ = $\frac{-1}{3}$ = - $\frac{1}{3}$

hence y = - $\frac{1}{3}$ x

when x = 9, then

y = - $\frac{1}{3}$ × 9 = - 3

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alina1380 [7]

When dealing with roots, we want to factor to see if it's possible

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The length of a rectangle is four times its width. If the perimeter of the rectangle is 20 feet, how many feet long is the recta

Gemiola [76]

Largeur = x
longueur = 4 x

2 ( x + 4 x) = 20
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3 years ago

What is the area of triangle abc below? If necessary, round your answer to two decimal places..... PLEASE PLEASE HELP ME

antiseptic1488 [7]

For a triangle:
$A=\frac{bh}{2}$
$A=\frac{b \times 7.9}{2}$
$b=AD+DC$
Use Pythagorean theorem twice:
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