Question

1. Solve the system of equations, y = x – 3 and y = –2x + 6, using the

2. Use the linear combination method to solve the system of equations.
–x + 5y = 18
x + 4y = 9

3. Solve this system of equations 3x + 5y = −72 and 2x + 3y = –45 using the
linear combination method. please help guys

Answer 1

1.

x=3,y=0

2.

x=-3,y=3

3.

x=-9,y=-9

Explanation:

1.

y=x-3

or

x-y=3 ...(1)

y=-2x+6

2x+y=6 ...(2)

(1)+1(2) gives

3x=9

x=9/3=3

y=3-3=0

2.

-x+5y=18 ...(1)

x+4y=9 ...(2)

(1)+1(2) gives

9y=27

y=27/9=3

x+4(3)=9

x=9-12=-3

3.

3x+5y=-72 ...(1)

2x+3y=-45

2(1)-3(2) gives

6x+10y-6x-9y=-144+135

y=-9

2x+3(-9)=-45

2x=-45+27=-18

x=-18/2=-9