The elimination method is ideal for solving this system of equations. By which number must you multiply the second equation to eliminate the y-variable, and what is the solution for this system? x + 3y = 42 2x − y = 14

Given:

The system of equations is

      ...(i)

       ...(ii)

To find:

The number that must be multiplied with the second equation to eliminate the y-variable.

Solution:

Coefficient of y variable in equation (i) is 3 and in equation (ii) is -1.

To eliminate y-variable the absolute value of coefficients of y-variables should be same.

So, we need to multiply the second equation by 3 to eliminate the y-variable

Multiplying equation (ii) by 3, we get

     ...(iii)

Adding (i) and (iii), we get

Divide both sides by 7.

Put x=12 in (i).

Divide both sides by 10.

Therefore, x=12 and y=10.

(0,-3) see attached graph

step-by-step explanation:

a. to solve the system, graph the two equations.

x = y+3 becomes y=x-3 has m=1/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move up 1 unit and 1 unit to the right. plot a point and connect.

y=-4x+3 has m =-4/1 and b=-3. start at (0,-3) on the y-axis and plot a point. then move down four units and to the right 1 unit. plot a point and connect.

the solution is the point (x,y) where the two lines intersect. by the graph below it is (0,-3).

b. to solve by substitution, substitute y = -4x-3 into x= y+3

x= (-4x-3) +3

x=-4x

5x=0

x=0

now substitute x = 0 back in to find y.

y= -4(0)-3

y=0-3

y=-3

solution is (0,-3)

c. use elimination by adding the equations together.

x-y=3

4x+y=-3

5x=0

x=0

then substitute into one equation to find y.

y=-4(0)-3

y=-3