If a varies directly as b, and a = 28 when b = 7, find b when a = 5. a 4/5 b 5/4 c 39.2

Option B.

Step-by-step explanation:

If a varies directly with b then when a increases b it also increases by a factor k.

Then we can write that

We know that when a = 28 then b = 7. So

Therefore the equation of proportionality is:

So when  then:

ANSWER

The correct choice is B.

EXPLANATION

If 'a' varies directly as 'b' then we write the equation of variation,

Where k is the constant of variation.

We have that a = 28 when b = 7.

This implies that,

The equation now becomes

When we a=5, we have

The correct answer is B

the correct answer is option c.   3

step-by-step explanation:

points to remember

equation of the line with coordinates (x₁, y₁) and (x₂, y₂) is given by,

slope m = (y₂ - y₁)/(x₂ - x₁)

from the figure we can see a line with two coordinates given

to find the slope of given line

here   (x₁, y₁)   = (-1, -1 ) and (x₂, y₂) = (1, 5)

slope m = (y₂ - y₁)/(x₂ - x₁)

  = (5 - -1)/(1 - -1)

  = (5 + 1)/(1 + 1)

  = 6/2 = 3

therefore the correct answer is option c.   3

4.

step-by-step explanation:

it have the same area.brainliest