Equation of a straight line.
posted by DJ Frankie Pigeon .
1. Find the equation of the line described in each case:
a) Gradient 3, cuts through (0, 6).
b) Steepness of 4, passes through (0, -2).
c)Parallel to y = 5x - 1, cuts the y-axis at (0, 10).
d)Cuts through (0, 7) and (5, 17)
2. Here are 3 eqautions:
A. y + 1 = 3x
B. y = -3(x - 1)
C. 2y = 8x + 6
Find the odd one out in each case:
a) Gradient is ±3
b) Slopes in a positive direction
c) Cuts the y-axis at (0, 3)
3. A line passes through the point (10, 10). It's equation is y = mx + 4. Find the value of m.
I'll try to get you started on these, and let you take it from there.
y - y1 = m(x - x1)
y - 6 = 3(x - 0)
y - 6 = 3x
y = 3x + 6
Use the same procedure as 1a.
Parallel lines have the same slope.
y - 10 = 5(x - 0)
I'll let you finish.
m = (y2 - y1)/(x2 - x1)
m = (17 - 7)/(5 - 0)
m = 10/5 = 2
Therefore, using the first ordered pair (0, 7), we have this:
(y - 7)/(x - 0) = 2
y - 7 = 2(x - 0)
I'll let you take it from here to finish.
The coefficient of x is the slope.
Look for positive slopes.
Substitute 0 for x and 3 for y in each equation to check each one.
Substitute 10 for x and 10 for y. Solve the equation for m, which is the slope.
I hope this will help get you started on these problems.
<<3. A line passes through the point (10, 10). It's equation is y = mx + 4. Find the value of m>>
Since y = mx + 4 and y = 10 when x = 10, plug those values of x and y into the eqwuation and solve for m.
Make an attempt at the others and we will glad to critique your work. Please limit your questions to one per post.