Solve the system of equations using elimination 3c - 8d =7 and c + 2d = -7

d=-2 c=-3

Step-by-step explanation:

3c-8d=7

4(c+2d=-7)

3c-8d=7

4c+8d=-28

4c+3c-8d+8d=7-28

7c=-21

c=-3

c+2d=-7

-3+2d=-7

2d=-4

d=-2

Given.

Multiply 4 to the second equation.

Compare the like terms.

Solve.

Divide 7 to both sides

Substitute (-3) for c into the original second equation.

Add (3) to both sides.

Divide (2) to both sides.

Check your work.

Therefore your answer is.

the solution is 12x-6y

answer: cos [   arcsin (3/5) - arccos (1/2) ] =

step-by-step explanation: × = 3/5 = 0.6--> x = 36.87 and x = 180 - 36.87 = 143.13 deg

cos y = 1/2 --> y = +- 60 deg a. cos (x - y) = cos (143.13 - 60) = cos 83,13  

=

0.12

b. cos (36.87 - 60) = cos (-23.23) = 0.92