Which property can be used to expand the expression -2(3/4x+7)

the associative property
the commutative property
the distributive property
the additive identity property

The distributive property

Step-by-step explanation:

Using the distributive property you can expand and simplify this expression:

-2(3/4x+7)

-2 x 3/4x + -2 x 7

-3/2x -14

y = 700x - 400

Step-by-step explanation:

Given:

When time x = 0 hours, her altitude is 400 meters below the sea level

and at time x = 2 hours, her altitude is 1000 meters above the sea level

Let the sea level be datum,

thus,

we get the coordinates of line as

at x = 0 , y = -400

at x = 2 , y = 1000

now,

The general equation for line is given as:

y = mx + c

here, m is the slope and c is the constant

therefore,

for (0, -400)

-400 = m(0) + c

or

c = -400 (1)

and,

for (2, 1000)

1000 = m(2) - 400           [c = -400 from 1]

or

1000 = 2m - 400

or

2m = 1400

or

m = 700

hence,

The equation between the altitude and number of hours is

y = 700x - 400