Question

Suppose y varies directly with x, and y = 10 when x = –3. What direct variation equation relates x and y? What is the value of y when x = –1?
A : y = –x;
B : y = x; –
C :y = x; –
D : y = –x;

Can somebody explain to me how to do this?

Answer 1

In this scenario, you need to understand what it means when y varies directly with x. Since they vary directly, as x increases, so does y. The proportion, also known as factor, stays constant no matter what you plug into x. This is fit by the following equation:
y=x


In other words, if you plug 5 into x, y should always no matter what be three times larger than x (just an example).

To solve this scenario, you need to find a proportion to use with your y = x formula. You can find the proportion by dividing y=72 by x=6.

72/6=12


Now, to use 12 in the formula. Remember that y is 12 times larger than x when you plug a number for x, so to make y larger, multiply 12 and x.
y=12x

let(x)→6

Plug 6 into x.

Therefore, y = 72 when x = 6.
y=12(6)=72

Answer 2

HElp?

Answer 3

?

Answer 4

very much, thank you (:

Answer 5

Best responge!