linear combinations to solve the linear system?

Question

3x+5=-16
-2x+6y=-36


i know that you subtract and if the #'s cant cancel you multiply by a # to make it = to the other # but i just cant figure out this one problem =/ yikes!!!

Answer 1

3x+5= -16.......(1)
2x+6y= -36......(2)
From eqn 1,we get
3x=-16-5= -21
or x= -21/3= -7
Substituting the value of x in eqn 2,we get
2*(-7)+6y= -36
or,-14+6y= -36
or,6y=-36+14= -22
or y= -22/6= -11/3 = -3 2/3
therefore,x=-7 and y= -3 2/3 ans.

Answer 2

3x + 15 = -16
3x = -16-5
x = -21 / 3
x = -7

substitute,
-2x + 6y = -36
-2(-7) + 6y = -36
14 + 6y = -36
6y = -36 - 14
y = -50 / 6
y = 25 / 3
y = 8 1/3

Answer 3

For sustitution method:
3x + 5 = -16
3x = -21
x = -7
Sub x = -7 into 2nd eqn
-2(-7) + 6y = -36
14 + 6y = -36
6y = -50
y = -8.33 (to 3 sig. fig.)

For elimination method:
1st eqn x 2 & 2nd eqn x 3.
6x + 10 = -32
-6x + 18y = -108
eqn 1 + eqn 2:
6x + 10 + (-6x + 18y) = -32 + (-108)
18y = -150
y = -8.33
Then solve for x using the 1st eqn.

Answer 4

(3x+5Y=-16
(-2x+6y=-36

Substitution:
Equation I:
3x = -16 - 5y
x = (-16 - 5y):3

Equation II:
-2(-16 - 5y):3 + 6y = -36
(32 + 10y):3 + 6y = -36
10y/3 + 6y = -36 - 32/3
28y/3 = -140/3
y = 140 : 28
y = 5

3x = -16 - 5y
3x = -16 - 5(5)
3x = -16 -25
3x = -41
x = -41/3
Solution: {(-41/3 and 5)}

IF
(3x+5 (no Y)=-16
(-2x+6y=-36

We'll have:
(3x = -16 - 5
(-2x + 6y = -36

Equation I:
3x = -21
x = -21:3
x = -7
Equation II:
-2x + 6y = -36
-2(-7) + 6y = -36
14 + 6y = -36
6y = -36 - 14
6y = -50
y = -25/3
Solution: {(-7 and -25/3)}
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Answer 5

Multiply the 1st equation by 3: -15x +6y =-30 then upload it to the 2d: -12x =-40 8 x=4 -5(4) +2y=-10 -20+2y=-10 2y=10 y=5 For the 2d device, multiply the 1st by 5:35x-20y=-15 and the 2d by 4: 8x+20y=-28 upload them:43x=-40 3 x=-one million 7(-one million)-4y=-3 -7-4y=-3 -4y=4 y=-one million

Answer 6

If you multiply the top equation by 2 and the bottom equation by 3, your x coefficients will be 6 and - 6. You can then ADD the equations to eliminate x. In this case you could just multiply the 2nd equation by 1.5 and still have integer coefficients to work with.

Answer 7

2 (3x+5=-16) ----> 6x+10= -32
3(-2x+6y=-36)---->-6x+18y= - 108
28y = -140
y= -5