Q&A for How to Calculate Slope and Intercepts of a Line

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  • Question
    How do I write an equation for the line with a slope of 6 and y-intercept of -3?
    Donagan
    Top Answerer
    Use the formula y = mx + b, where m is the slope and b is the y-intercept.
  • Question
    How do I write the equation of a line, given the slope and y-intercept?
    Donagan
    Top Answerer
    Assuming you're talking about a linear (straight-line) equation, you would use the standard slope/y-intercept form, y = mx + b. Use the given slope for m, the coefficient of x. Use the given y-intercept for b, the constant in the equation. For example, if the slope is 3 and the y-intercept is -5, the equation would be y = mx + b = 3x + (-5) = 3x - 5.
  • Question
    What is intercept and how do I calculate this using a graph?
    Community Answer
    There are two types of intercept, x-intercept and y-intercept. When we say x-intercept, this means the line passes through the x-axis with coordinates (x,0). When we say y-intercept, the graph passes through the y-axis with coordinates (0,y). To find x or y intercepts, just observe where the line on the graph cuts the x or y axis respectively.
  • Question
    What is simultaneous linear graph?
    Donagan
    Top Answerer
    That is a graph showing more than one function, equation, or line.
  • Question
    If point (-2,-4) has a slope of 4, what is the equation?
    Donagan
    Top Answerer
    The standard equation is y = mx + b, where m is the slope, and b is the y-intercept. The slope is given as 4. Thus, y = 4x + b. The point (-2,-4) fits into the equation, so we can insert those x and y values into the equation. Thus, -4 = 4(-2) + b = -8 + b. Adding 8 to both sides of the equation results in 4 = b. Thus, the equation we're looking for is y = mx + b = 4x + 4.
  • Question
    What is the slope of a line that has a y intercept of 5 and an x intercept of -5?
    Orangejews
    Community Answer
    With two points, (0,5) and (-5,0), you can compute slope directly by dy/dx. The slope = dy/dx = (5-0)/(0-(-5))= 1.
  • Question
    If the x interecept is -3/4 and the line passes through the points -2,1/3 what is the slope?
    Community Answer
    You are given two points: (-3/4, 0) and (-2, 1/3). Slope is defined as rise over run or delta y over delta x, so plug the known coordinates into that formula. Slope = (0 - 1/3) / (-3/4 - (-2)) = (-1/3) / (5/4) = -4/15.
  • Question
    How do I find the y-intercept of the equation 2(x-1)^2 + 5?
    Donagan
    Top Answerer
    The y-intercept occurs when x=0. So substitute 0 for x in the equation, and solve for y. y = 2(x-1)² + 5. Substituting 0 for x: y = 2(0-1)² + 5 = 2(-1)² + 5 = 2(1) + 5 = 2 + 5 = 7. So y is 7 when x is 0, and the y-intercept is 7.
  • Question
    How can I find a correct scale for a graph?
    Donagan
    Top Answerer
    Take the maximum quantity to be represented on either axis, and divide it by the number of units available on that axis. The quotient will be the quantity to be represented by each unit. This can be done separately for each axis, although typically a single scale is used for both axes.
  • Question
    How do I find x and y of a line?
    Community Answer
    X is the sideways line, y is the upwards/downward line. Namely, x is vertical, y is horizontal.
  • Question
    How do I get the intercept of Y if a line doesn't cross the Y axis?
    GB742
    Top Answerer
    If the line never crosses the Y axis, there isn't a Y intercept, so it's not possible to find this. There are plenty of functions that don't intercept the Y intercept, so don't worry if you can't find it.
  • Question
    ax + by = c (a,b,c can be random numbers), how do I work out the slope?
    GB742
    Top Answerer
    To work out the slope of the line, you can rearrange the function into the form y=mx+c. In your example, this would be rearranged as by=c-ax -> y=(c-ax)/b -> y = (c/b)-(a/b)x. Therefore, the slope of your line would be -(a/b).
  • Question
    How do I calculate the Y-intercept if not given?
    GB742
    Top Answerer
    To find the y-intercept, substitute x with 0. If the function of the line was y=7x+5: y=7(0)+5 -> y= 0+5 -> y=5, therefore, the line intercepts y at the point (0,5).
  • Question
    What is the slope of a line that passes through A(9,5) and B(7,-3)?
    GB742
    Top Answerer
    To calculate the gradient of a line between two points, you can use the formula m = (y2 - y1)/(x2-x1). In your example: m = (-3 - 5)/(7 - 9) -> m = (-8)/(-2) -> m = 4.
  • Question
    If I want to find the slope of 5x - 2y = 20, what should I do?
    Community Answer
    Change the equation into the slope-intercept form (y = mx + b). First subtract 5x from both sides: -2y = -5x + 20. Then divide both sides by -2: y = 5/2x - 10. That's the slope-intercept form. That means m = 5/2, which is the slope.
  • Question
    How can I memorize the parts in the equation y=mx+b?
    I_l1ke_gam3s
    Community Answer
    In this equation, y and x are points on a line on a coordinate plane. M represents the slope and b represents the y-intercept and both values are constants.
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