Solve the system by addition. 3x + y = –1 9x + 3y = –3?

Question

Solve the system by addition. 3x + y = –1 9x + 3y = –3

Answer 1

A) 3x + y = –1
B) 9x + 3y = –3

Multiply B by 1/3 and you get
C) 3x + y = -1

Therefore, Equation (A) = Equation (B) And you only have one equation with two unknowns... Can't be solved.

Answer 2

Hi,

3x + y = –1
9x + 3y = –3

To solve by addition, multiply the first equation by -3 and add them together. The x term will drop out.

-3(3x + y = –1)
9x + 3y = –3

-9x - 3y = 3
9x + 3y = –3
-------------------
0 = 0

This time both variables dropped out, giving a true identity. Since 0 always equals zero, then the lines intersect at every point on either equation. they are actually the same equation in slope-intercept form, so there are an infinite number of points that are the solution to this system.

I hope that helped!! :-)

Answer 3

PLEASE REWRITE YOUR 2 EQUATIONS.
With what you have right now, it does not seem likely that there is as solution to the question you are being asked.

OTHERWISE, going with what you gave us:
3x + y = –1
Multiply this equation by 3 to you can solve, so
(3x + y = –1)*3
9x + 3y = -3

You can see this is the same as the second equation, so any value of x and y works, thus, there is an unlimited amount of solutions.

9x + 3y = -3 (1st equation)
9x + 3y = –3 (2nd equation)

Answer 4

3x+y=-1
9x+3y=-3
i dont see how u wud solve this by addition.
but, we can use other methods to solve for x and y.
3x+y=-1
9x+3y=-3
now, we can see very easily that the first equation=3*the second equation.
from the first equation, we know:
3x+y=-1
y=-1-3x
y=-(3x+1)
inputting this in the second results to:
9x+3(-(3x+1))=-3
9x-3(3x+1)=-3
9x-9x-3=-3
-3=-3
this means that the equation cannot be solved, because as i said, the second equation is basically 3* the first. please check ur equations to make it possible to solve.
sorry.

Answer 5

3x + y = - 1
y = - 1 - 3x

9x + 3y = - 3
3x + y = - 1
y = - 1 - 3x

There seems to be no solution to this problem.