Question

ok i figured out the substitution. how do i do elimination?

Solve –x + 2y = 12 using the elimination method.
x + 6y = 20

Answer 1

add both eqns
8y = 32
y = 4
put in x +6y =20
x + 24 = 20
x = -4

x= -4 and y = 4

Answer 2

u add both parts --->
x-x+2y+6y=12+20
8y=32
y=32/8=4
then u replace y with 4 at 1 of those eq:X+6*4=20
X=-4

Answer 3

Solve 9x + 2y = 2 by the elimination methods.
21x + 6y = 4
and for that problem would i combine all the signs too" or should i pick one

Answer 4

9x + 2y = 2 In this case u multiply the 1sr eq with a (-3) and u'll have
21x + 6y = 4

-27x-6y=-6
21x+6y=4 (+)
-6x=-2
x=1/3
21*1/3+6y=4
7+6y=4
6y=-3
y=-1/2

Answer 5

understand?

Answer 6

see here u will hv to make the coefficient of either x ort y equal by multiplying by suitable nos and then subtracting second fr first as follows
first by 3 : 27x + 6y = 6 (A)
second by 1 : 21x + 6y = 4 (B)
(A) - (B) gives 6x = 2 so x = 1/3

Put this in first eqn
9(1/3) + 2y = 2
3 + 2y = 2
2y = 2-3
y = -1/2

Answer 7

ooh ok i get it thanks! now i can do the rest of the problems.

Answer 8

U w :)