Question

If y varies directly with x and y = -7 when x = -1, find x when y = -84.
A. 84
B. 7
C. -12

Answer 1

Substitute again and check which equation satisfies.

Answer 2

Oh, wait. Set up a proportion and solve. Do you know how?

Answer 3

y = kx

Answer 4

\(\Large \color{MidnightBlue}{\Rightarrow -1:-7::x:-84 }\)

Answer 5

Here, I've set it up.

Answer 6

\(\Large \color{MidnightBlue}{\Rightarrow -7x = 84 }\)

Answer 7

Solve it now! :D

Answer 8

y = -7 x = -1

-7 = -1k

Answer 9

@ZhangYan KISS principle. If y varies directly with x, then it means that they are in proportion.

Answer 10

oh right...^^follow his steps :D