Question

Solve each system by elimination 6x+3y=21 -12x+y=-7

Answer 1

Answer:

x=1,y=5

Step-by-step explanation:

6x+3y=21....(1)

-12x+y=-7.....(2)

From (2) make y the subject of formula

y=-7+12x...(3)

Substitute (3) into (1)

6x+3(-7+12x)=21

6x-21+36x=21

Collect like terms

6x+36x=21+21

42x=42

Divide both sides by 42

x=1

Substitute the value of x into (3)

y=-7+12(1)

y=-7+12

y=5

Therefore x=1,y=5

Answer 2

Answer:

(x,y)=(1,5)

Step-by-step explanation:

6x+3y=21/*2

-12x+y=-7

12x+6y=42 (1)

-12x+y=-7 (2)

(1)+(2): 7y=35

-12x+y=-7

y=35/7

-12x+y=-7

y=5

-12x+5=-7

y=5

-12x=-7-5

y=5

-12x=-12

y=5

x=-12/(-12

y=5

x=1

(x,y)=(1,5)