Answer:
43.82 mph
266.67 feet
Step-by-step explanation:
Given :
S = √30fl
S = speed of car
f = drag Coefficient
l = Length of skid mark
If f = 0.8 ; l = 80 feets
s = √30fl
s = √(30*0.8*80)
s = √1920
s = 43.817
s = 43.82 mph
B.)
s = 80 mph
f = 0.8
s = √30fl
80 = √30*0.8*l
80 = √24l
Square both sides
80² = 24l
6400 = 24l
l = 6400/24
l = 266.67 feets
Answer: (4, -9)
<u>Step-by-step explanation:</u>
Use elimination method. Manipulate one (or both) equations to eliminate one of the variables and solve for the remaining variable. <em>I will be eliminating y</em>
6x + y = 15 → 2(6x + y = 15) → 12x + 2y = 30
-7x - 2y = -10 → 1(-7x + 2y = -10) → <u> -7x - 2y = -10</u>
5x = 20
x = 4
Next, replace "x" with "4" into either equation and solve for y.
6(4) + y = 15
24 + y = 15
y = -9
<u>Check:</u>
Plug in x = 4 and y = -9 into the other equation to verify it makes a true statement.
-7x - 2y = -10
-7(4) - 2(-9) = -10
-28 - -18 = -10
-28 + 18 = -10
-10 = -10 
Step-by-step explanation:
Since the options are not clear enough, please kindly see the attached file for more explanation