If 3x+5y=2 and 2x-6y=20 what is 5x-y

22

Step-by-step explanation:

3x + 5y = 2 equation 1

2x - 6y = 20 equation 2

solving the system of linear equation by elimination method. Multiply equation 1 by 2 and equation 2 by 3 , then we have

6x + 10y = 4 equation 3

6x - 18y = 60 equation 4

subtract equation 3 from equation 4 , then we have

-28y = 56

divide through by -28

y = -2

substitute y = 2 into equation 1 to find the value of x , then we have

3x + 5 (-2) = 2

3x - 10    = 2

3x = 2 + 10

3x = 12

x = 4

Therefore :

5x - y = 5 (4) - (-2)

          = 20 + 2

          = 22

f(x) has value 150 at x= 0

and 0 at x= 3

so d(f(x))/dt = slope = -150/3 = -50