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:
Answer:
(a)= option 3
(b)= option 3
Step-by-step explanation:
(A) It is given that a sequence is defined by the recursive function
and 
Now, substituting the value of n=2 in above equation,



Again putting n=3,



Putting n=4,



Putting n=5,



Putting n=6,



Putting n=7,



Hence, option 3 is correct.
(B) The given sequence is :
5, -10, 20, -40, 80.....
Since, the given sequence is GP, therefore
and r=-2
The nth term is given by:

For fifteenth term, put n=15 in above equation, we get

=
=
Hence, the fifteenth term is 81920.
Option 3 is correct.
Answer:
3x^2+15x-1=0
Step-by-step explanation:
4/(3x+15)=4x
4=12x^2+60x
12x^2+60x-4=0
3x^2+15x-1=0
Please solve after that, I cannot do everything for you
Answer: B. 70
Step-by-step explanation:
i actually can't tell but i think this is right