Answer:
Step-by-step explanation:
Part A: 15
Part B: $125
I assume you are being asked to solve these equations. Since there wasn't an explanation as to how you are expected to solve them, I chose to demonstrate how to use a calculator matrix function. You can find matrix calculators online. My instructions are for a TI-84
Push the blue 2nd button then push x^-1 button (it says matrix above this button in blue)
Arrow over to edit to change the dimensions of the matrix and to put in your values. You have 3 equations (3 rows) and 4 terms (4 columns) so you put a 3x4 in for the dimension and the coefficients (see images).
You use the rref option in the math column in matrix to calculate the answer.
The numbers at the end are the solutions. x = -4, y = 2, z = -1
Answer:
The Law of Cosine : cos C = 
Step-by-step explanation:
See the figure to understand the proof :
Let A Triangle ABC with sides a,b,c,
Draw a perpendicular on base AC of height H meet at point D
Divide base length b as AD = x -b and CD = x
By Pythagoras Theorem
In Triangle BDC And In Triangle BDA
a² = h² + x² ( 1 ) c² = h² + (x-b)²
c² = h² + x² + b² - 2xb ...(. 2)
From above eq 1 and 2
c² = (a² - x²) + x² + b² - 2xb
or, c² = a² + b² - 2xb .....(3)
Again in ΔBDC
cos C = 
Or, cos C = 
∴ x= a cos C
Now put ht value of x in eq 3
I.e, c² = a² + b² - 2ab cos C
Hence , cos C =
Proved Answer
Answer:
2 tickets
Step-by-step explanation:
hope it is right
Answer:
Gray family's sprinkler was used for 40 hours.
Thompson family's sprinkler was used for 35 hours.
Step-by-step explanation:
The Gray family and the Thompson family each used their sprinklers last summer.
Let x= amount of time in hours that the Gray family's sprinkler was used.
Let y = amount of time in hours that the Thompson family's sprinkler was used.
The water output rate for the Gray family's sprinkler was 40 L per hour. The water output rate for the Thompson family's sprinkler was 20 L per hour. This means that the combined number of hours that both family's used their sprinklers is 40x + 20y
The families used their sprinklers for a combined total of 75 hours, resulting in a total water output of 2300 L .
This means
x + y = 75
40x + 20y = 2300 - - - - - - - -1
Substituting x = 75 -y into equation 1,
40 ( 75 - y ) + 20y = 2300
3000 - 40y + 20y = 2300
-40y + 20y = 2300 - 3000
-20y = -700
y = 700/20 = 35 hours
x = 75 - y
x = 75 -35 = 40 hours