solve the following simultaneous equation graphically x - 3y = -9 and 2x - 3y + 12 = 0?

Question

a sketch is to be included in your solution

Answer 1

x - 3y = - 9- - - - - -Equation 1
2x - 3y + 12- - - - - Equation 2
- - - - - - - - - -
Multiply equation 1 by negative 1 and convert equation 2 to standard form

x - 3y = - 9

- 1(x) - (- 1)( 3y) = - 1( - 9)

- x - (- 3y = - (- 9)

- x + 3y = 9]

- - - - - - - - -

2x - 3y + 12 = 0

2x - 3y + 12 - 12 = 0 - 12

2x - 3y = - 12

- - - - - - - - -

- x + 3x = 9
2x - 3y = - 12
- - - - - - - - - - -
x = - 3

Insert the x value into equation 1

x - 3y = - 9

- 3 - 3y = - 9

- 3 - 3y + 3 = - 9 + 3

- 3y = - 6

- 3y / - 3 = - 7 / - 3

y = - 6 / - 3

y = 2

Insert the y value into equation 1

- - -

Check for equation 1

x - 3y = - 9

- 3 - 3(2) = - 9

- 3 - 6 = - 9

- 9 = - 9

- - - - - - - - -

Check for equatio 2

2x - 3y + 12 = 0

2(- 3) - 3*2) + 12 = 0

- 6 - 6 + 12 = 0

- 12 + 12 = 0

0 = 0

- - - - - - - - - -

The solution set { - 3, 2 }

- - - - - - - - - -s-

Answer 2

x - 3y = -9 (i)
2x-3y =-12 (ii)
By subtracting (ii) by (i) -x = 3
Hence x = -3
By substituting x = -3 in eqn (i) -3 -3y = -9
-3y = -9 +3
-3y = -6
y = 2
Hence x = -3 and y = 2

Answer 3

given, x - 3y = -9 ......................(1)
2x - 3y + 12 = 0 .................(2)

from (1) x = -9 + 3y ...................(3)
substitute (3) into (2), so, 2(-9 + 3y) - 3y +12 = 0
-18 + 6y - 3y + 12 = 0
3y - 6 = 0
3y = 6
y = 2 ....................(4)
substitute (4) into (3), so, x = -9 + 3(2)
x = -9 + 6
x = -3

Answer: x = -3 and y = 2

Answer 4

They are both straight lines.
First has its intersects at (-9,0) and (0,3)
Second cuts the axes at (-6,0) and (0,4)
So draw lines through these points and the answer is where they cross. A sketch is fine, make sure you clearly label the axes intersects and the solution point. You should find it to be (-3,2)

Answer 5

Just plot the graph for each straight line equation and the intersection of the 2 lines is the solution (x, y)

Answer 6

x = ?
y = ?

x - 3y = -9
2x - 3y + 12 = 0?

2x - 3y = -12
ermm..........
-12 -
- 9
------
3


x=3
3x2=6
-12
-6
----
6

y=6
x=3
and i'm 13 so i've probily got it wrong

Answer 7

x - 3y = -9 (-2)
and
2x - 3y = -12

-2x + ¨6y = 18
2x - 3y = -12
-------------------
3y = 6
y = 6: 3
y = 2

x - 3y = -9
x - 3(2) = -9
x = -9 + 6
x = -3
Answer: {(-3,2)}
><>

Answer 8

x= -21
y= -18