What is the equation of a straight line passing through two points?

In summary, the equation of a straight line passing through (1,4) and (5,1) is y=-(3/4)x+c, with a slope of -3/4. To find the y-intercept, substitute the given points into the equation and solve for c.
  • #1
jahlin
21
0

Homework Statement



whats the equation of a straight line passing through (1,4) and (5,1)?

Homework Equations


y=mx+c


The Attempt at a Solution



i found the equation to be y=-(3/4)x is it right?
Thanks
 
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  • #2
No it's not right. How did you get y=(-3/4)x? The slope is right. The c part isn't.
 
  • #3
well it doesn't intercept with the y-axis so i assumed it to be zero..
 
  • #4
hi
actually the straight line intercepts with y-axis. you can substitute the x value and y value into the equation you found. Obviously they cannot fit.
so the gradient you get is -3/4, which is the correct one.
y = (-3/4)x + c;
one way to find c is by substituting (1, 4) into equation stated above.
then the correct equation of the straight line passing through two points can be found.

Cheers,
weesiang_loke
 

1. What is the equation of a straight line?

The equation of a straight line is represented in the form y = mx + b, where m is the slope of the line and b is the y-intercept. This equation can also be written as Ax + By = C, where A and B are the coefficients of x and y, and C is a constant.

2. How do you find the slope of a straight line?

The slope of a straight line is the rate of change between any two points on the line. It can be calculated by taking the difference in y-coordinates divided by the difference in x-coordinates, or (y2 - y1) / (x2 - x1). This can also be represented as rise over run.

3. What is the significance of the y-intercept in the equation of a straight line?

The y-intercept is the point where the line crosses the y-axis. It represents the initial value of y when x is equal to 0. In other words, it is the value of y when x is not present in the equation. The y-intercept can also indicate the starting point or the initial condition of a function or relationship.

4. Can the equation of a straight line be used to represent nonlinear relationships?

No, the equation of a straight line only represents linear relationships. Nonlinear relationships can be represented using other types of equations such as quadratic, exponential, or logarithmic.

5. How do you graph a straight line using its equation?

To graph a straight line using its equation, plot the y-intercept first, and then use the slope to find one or more additional points on the line. Connect these points with a straight line to create the graph. Alternatively, you can use the slope-intercept form (y = mx + b) to graph the line by plotting the y-intercept and using the slope to find other points or by using the point-slope form (y - y1 = m(x - x1)) and a specific point on the line to graph it.

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