Solve each system by elimination

6x+3y=21
-12x+y=-7

(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)

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

step-by-step explanation:

you can add the two numbers and divide the result by 2. or you can find the gap between the two numbers and add half of this to the smaller number.