Question

20 POINTS!!!!

Solve by the linear combination method (with or without multiplication).

x + y = 100
0.07x + 0.05y = 5.8

a. ( 20, -50 )

b. ( 50, 50 )

c. ( 10, 30 )

d. ( 40, 60 )

Solve by the linear combination method (with or without multiplication).

3x - 5 = 7
2x + 3y = 30

a. ( 3, 7 )

b. ( 9, 4 )

c. ( 3, -7 )

d. ( -3, -7 )

Answer 1

Answer:

The correct answer is d. (40, 60)

Step-by-step explanation:

To start using the linear combination method, you need a variable that will cancel out. To get this, we will multiply the second equation by -20 and then add together.

x + y = 100

-1.4x - y = -116

-----------------

-0.4x = -16

x = 40

Now that we have the value of x, we plug into one of the original equations to find y.

x + y = 100

40 + y = 100

y = 60