Question

If y varies directly as x and y = 5 when x = 8, find y when x = 9. a. 75/2 b. 45/8 c. 40/9 d. 6

Answer 1

X= 24 because y=Kx and 5=k(8) so then that means k=58. Now y=58 then multiply and get y=15 once u distribute. Y =58

15= 0.625x

150.625=x

24=x

Answer 2

Explanation:

first derive a formula from that expression

y=kx

in this case k its a constant so we will find a constant first in order to derive a formula

substitute the variables with numbers been given

5=k(8) then make k subject of the formula

k=58 then make a formula from the constant

y= 58x

now this is your direct linear equation y= 58x

then use that equation in order to find the x value

finding x value, substitute the formula with the value given in this case y=15

then

y= 58x

15= 0.625x

150.625=x

24=x

therefore x =24