Abedabun wants to model how a car's maintenance costs change as the distance someone drives the car increases.
what would be an appropriate unit for abedabun's purpose?

the value of x is 9 ⇒ answer b

step-by-step explanation:

* we can solve this problem using cosine and sine rule

- in δ abc

∵ ab = 36 , bc = 28 , ac = 16

- lets find the measure of angle b using the cosine rule

∵ cos b = [ab² + bc² - ac²]/2(ab)(bc)

∴ cos b = [36² + 28² - 16²]/2(36)(28)

∴ cos b = 19/21

∴ m∠b = cos^-1(19/21) ≅ 25°

- lets find the measure of angle a using the sine rule

∵ sina/bc = sinb/ac = sinc/ab

∴ sina/28 = sin25°/16 ⇒ by using cross multiplication

∴ sina = 28 × sin25°/16

∴ sina = 0.7396

∴ m∠a = sin^-1(0.7396) ≅ 48°

- from the figure m∠abd = m∠dbc

∵ m∠abc = 25°

∴ m∠abd = 25°/2 = 12.5°

- in δabd

∵ m∠a = 48° , m∠abd = 12.5°

∵ the sum of the measures of the interior angles of any δ is 180°

∴ m∠adb = 180° - (48° + 12.5°) = 119.5°

∵ ab = 36

∵ ad = x

- use the sine rule to find x

∵ sin∠adb/ab = sin∠abd/x

∴ sin119.5°/36 = sin12.5°/x ⇒ by using cross multiplication

∴ x = 36 × sin12.5°/sin119.5° = 8.95 ≅ 9

* the value of x is 9

d: (13,-1)

step-by-step explanation:

we know the starting point is (1,5)

the ending point is (x,y)   (cristians house)

the total distance is 6 units (5: 1)  

the fast food restaurant is at (11,0) and is 5/6ths of the way from the starting point to the ending point

ending minus starting point * 5/6   is how far they went

(x-1) *5/6, (y-5) * 5/6

we then need to add the starting point to determine the location

5/6(x-1) + 1, (y-5) * 5/6 + 5

this equals the fast food location of 11,0

setting the x locations equal

5/6 (x-1) +1 =11

subtracting 1 from each side

5/6 (x-1) +1-1 =11-1

5/6(x-1) =10

multiplying by 6/5 on each side

6/5*5/6(x-1) = 10*6/5

x-1 =12

add 1 to each side

x-1+1 =12+1

x=13

do the same for the y coordinate

(y-5) * 5/6 + 5 =0

subtract 5 from each side

(y-5) * 5/6 + 5-5 =0-5

5/6 (y-5) = -5

multiplying by 6/5 on each side

6/5*5/6 (y-5) = -5 *6/5

y-5 = -6

add 5 to each side

y-5+5 = -6+5

y=-1

the ending point , or the coordinates of cristians house is

(13,-1)