Answer:
Solving systems of equations with 3 variables is very similar to how we solve systems with two variables. When we had two variables we reduced the system down
to one with only one variable (by substitution or addition). With three variables
we will reduce the system down to one with two variables (usually by addition),
which we can then solve by either addition or substitution.
To reduce from three variables down to two it is very important to keep the work
organized. We will use addition with two equations to eliminate one variable.
This new equation we will call (A). Then we will use a different pair of equations
and use addition to eliminate the same variable. This second new equation we
will call (B). Once we have done this we will have two equations (A) and (B)
with the same two variables that we can solve using either method. This is shown
in the following examples.
Example 1.
3x +2y − z = − 1
− 2x − 2y +3z = 5 We will eliminate y using two different pairs of equations
5x +2y − z = 3
Step-by-step explanation:
Subtract 20 from 40 then divide by 10
C=2
Answer:
STAN LOONA
Step-by-step explanation:
7x - 1 + 6x - 1 = 180
add the x’s, add the numbers
13x - 2 = 180
add 2 to 180
13x = 182
divide 182 by 13
x = 14
Answer in fraction form = 9/8
Answer in decimal form = 1.125
note: the improper fraction 9/8 converts to the mixed number 1 & 1/8
To get this answer, we divide both sides by 8 to isolate n. The expression 8n really means "8 times n". We divide to undo the multiplication.
