Sung-Hi is filling a sandbox with sand at the rate shown in the table below. Which statement must be true regarding the linear function that represents this situation? Amount of Sand in the Sandbox
Number of Minutes Since Sung-Hi Started
0
1
2
3
4
Amount of Sand in the Sandbox (pounds)
200
220
240
260
280
The initial value must be 0 pounds.
The initial value must be 20 pounds.
The rate of change must be 0 pounds per minute.
The rate of change must be 20 pounds per minute.

11.2

step-by-step explanation:

when doing tangent the tangent of the angle is equal to the opposite side from the angle over the adjacent side to the angle.

tan43 = x / 12

move 12 over by multiplying each side by 12

12tan43 = x

x = about 11.2

x^2 + 81

we can factor this using difference of square binomials.

rewrite the equation:

x^2 - (-81)

factor:

(a^2 - b^2) = (√a^2 + √b^2)(√a^2 - √b^2)

(x^2 - (-81) = (x + √-81)(x - √-81)

we can remove the - from under the radical by multiplying it by i.

(x^2 - (-81) = (x + i√81)(x - i√81)

(x^2 - (-81) = (x + 9i)(x - 9i)

we can check our answer by using foil:

x^2 - 9ix + 9ix - 81i^2

x^2 - 81^2

i^2 = -1

x^2 + 81

x< -17/2 hope this