7x+2y=-19 - x+2y=21 i need the substitution

7x + 2y = 19

-x + 2y = 21

7x + 2y = 19

Subtract 2y from both sides

7x = 19 - 2y

Divide both sides by 7

x = (-2/7) y - (19/7)

x + 2y = 21

Substitute x for (-2/7) y - (19/7)

(-2/7) y - (19/7) + 2y = 21

Combine like terms

(12/7) y - (19/7) = 21

Add (19/7) to both sides

(12/7) y = (166/7)

Multiply both sides by (12/7)

y = (83/6)

x + 2y = 21

Substitute y for (83/6)

x + 2 (83/6) = 21

Multiply 2 by (83/6)

x + (83/3) = 21

Subtract (83/3) from both sides

x = (-20/3)

x = (-20/3)

y = (83/6)