Answer: Y = - 4 & x = 1
Step-by-step explanation:
Systems of linear equations: We will solve this using substitution but you can use 2 more ways.
7x + 2y = -1
2x - 4y = 19
Leave X alone first: -------------------
10x - 2y = 18
10x/10 = 18 + 2y/10
x = 9/5 + y/5
Solve for y:
7(9/5 + y/5) + 2y = -1
63/5 + 7y/5 + 2y - 1
63/5 + 7y/5 = 10y/5 = -1
63/5 + 17y/5 = -1 (-5/5)
17y/5 = -68/5 (cancel the 5)
y = -68/17
y = - 4 (Your Answer)
7x + 2(- 4) = -1
7x + (-8) = -1
7x = 7
x = 1
CHECK=
7(1) + 2(-4) = -1
7+ (-8) = -1.
-1=-1
I'd suggest using "elimination by addition and subtraction" here, altho' there are other approaches (such as matrices, substitution, etc.).
Note that if you add the 3rd equation to the second, the x terms cancel out, and you are left with the system
- y + 3z = -2
y + z = -2
-----------------
4z = -4, so z = -1.
Next, multiply the 3rd equation by 2: You'll get -2x + 2y + 2z = -2.
Add this result to the first equation. The 2x terms will cancel, leaving you with the system
2y + 2z = -2
y + z = 4
This would be a good time to subst. -1 for z. We then get:
-2y - 2 = -2. Then y must be 0. y = 0.
Now subst. -1 for z and 0 for y in any of the original equations.
For example, x - (-1) + 3(0) = -2, so x + 1 = -2, or x = -3.
Then a tentative solution is (-3, -1, 0).
It's very important that you ensure that this satisfies all 3 of the originale quations.
Answer:
36
Step-by-step explanation:
18=a/2
2*18=a
36=a
I tried just give it to me anyway