{2x+9=y
{y=-4x-3
Get some point of each line.
Get some arbitrary points on the line for the first equation
2x + 9 = y |2x + 9 = y |2x + 9 = y
Let x = 0, then |Let x = -4, then |Let x = -8, then
2(0) + 9 = y |2(-4) + 9 = y |2(-8) + 9 = y
9 = y | -8 + 9 = y | -16 + 9 = y
| 1 = y | -7 = y
So one point is (0,9) |So one point is (-4,1) |So one point is (-8,-7)
Let's plot those three points:
Let's draw a line through them.
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{y=-4x-3
Get some arbitrary points on the line for the second equation
y = -4x - 3 |y = -4x - 3 |y = -4x - 3
Let x = 0, then |Let x = 1, then |Let x = -3, then
y = -4(0) - 3 |y = -4(1) - 3 |y = -4(-3) - 3
y = 0 - 3 |y = -4 - 3 |y = 12 - 3
y = -3 |y = -7 |y = 9
So one point is (0,-3)|So one point is (1,-7) |So one point is (-3,9)
Let's plot those three points:
Let's draw a line through them.
Maybe you can tell what that point of intersection is just by
looking. If you can't, draw a vertical line straight down from
that point to the x-axis and one horizontal over to the y-axis:
The vertical line intersects the x axis at -2
The horizontal line intersects the y-axis at 5.
So the point of intersection is (-2,5)
The solution is x = -2 and y = 5
Edwin
