Solve the system of equations by substitution. 6 = −4x + y −5x − y = 21solve the system by the elimination method. 2x + y = 20 6x – 5y = 12

6 = −4x + y

−5x − y = 21  

 (-3, -6)

2x + y = 20 6x – 5y = 12  

(7 , 6)

Step-by-step explanation:

Solve the system of equations by substitution.

6 = −4x + y --> y = 4x + 6

−5x − y = 21

Substitute y = 4x + 6 into −5x − y = 21

−5x − (4x + 6) = 21

-5x - 4x - 6 = 21

-9x = 27

  x = - 3

y = 4(-3) + 6

y = -12 + 6

y = -6

(-3, -6)

Solve the system by the elimination method.

2x + y = 20

multiply the equation by (-3) ; 2x + y = 20  so

-6x - 3y = - 60

6x – 5y = 12

add

-8y = - 48

  y = 6

2x + y = 20

2x + 6 = 20

2x = 14

 x = 7

(7 , 6)