Georgiy Posted September 30, 2019 Share Posted September 30, 2019 How to find an equation of a line can anyone explain please? Link to comment Share on other sites More sharing options...

sangui Posted September 30, 2019 Share Posted September 30, 2019 Do you have any precision ? Link to comment Share on other sites More sharing options...

Georgiy Posted September 30, 2019 Author Share Posted September 30, 2019 Just explain me the method please, as I'm lost Link to comment Share on other sites More sharing options...

druS Posted October 1, 2019 Share Posted October 1, 2019 y = m.x + c m is the slope. c is the y axis intercept How you get there depends on the starting information. Link to comment Share on other sites More sharing options...

Country Boy Posted October 21, 2019 Share Posted October 21, 2019 (edited) Your question is simply too vague. Find the equation of a line given what information? Most common is "find the equation of the line through two given points". But you could also be asked to "find the equation of the line through a given point having a given slope" or "find the equation othf the line through a given point parallel to a given line" or "find the equation of the line through a given point perpendicular to a given line". Any (non-vertical) line can be written "y= ax+ b". If you are given two points you can put the x, y coordinates into that equation to get two equations to solve for a and b. For example, if the two points are (3, 5) and (7, 9) then we have 5= 3a+ b and 9= 7a+ b. Subtracting the first equation from the second, 4= 4a so a= 1. Then 5= 3+ b so b= 5- 3= 2. The line is given by y= x+ 2. If you are given the point (3, 5) and slope 3 then, because the "a" in "y= ax+ b" is the slope, a= 3. Putting the x= 3, y= 5 in y= 3x+ b we have 5= 3(3)+ b so b= 5- 9= -4. The line is given by y= 3x- 4. If you are given the point (3, 5) and are told that the line is parallel to the line y= 7x+ 9 then the slope is the same as the slope of the given line, 7, so we have the previous problem: 5= 7(3)+ b. b= 5- 21= -16. The line is given by y= 7x- 16. If you are given the point (3, 6) and are told that the line is perpendicular to the line y= 4x- 5 then the slope is the negative reciprocal of the slope of the given line, -1/4, so we gave 6= (-1/4)(3)+ b. b= 6+ 3/4= 27/4. The line is given by y= (-1/4)x+ 27/4. We can also write that as 4y= 27- x or x+ 4y= 27. (Any vertical line can be written x= constant. The x-value of a given point on the line gives you the constant.) Edited October 21, 2019 by Country Boy 1 Link to comment Share on other sites More sharing options...

oliholbourns Posted November 28, 2019 Share Posted November 28, 2019 (edited) Well, first of all, we need to know is it a straight line? then, as druS mentioned, we may use the equation y = mx + c for a straight line. Also can I just ask if I am correct in saying that neutrinos are the smallest things in the world? Edited November 28, 2019 by oliholbourns Link to comment Share on other sites More sharing options...

Strange Posted November 28, 2019 Share Posted November 28, 2019 2 minutes ago, oliholbourns said: Also can I just ask if I am correct in saying that neutrinos are the smallest things in the world? ! Moderator Note You can ask that in the Physics forum. (No, they are the same size as all other fundamental particles) Link to comment Share on other sites More sharing options...

oliholbourns Posted November 28, 2019 Share Posted November 28, 2019 29 minutes ago, Strange said: ! Moderator Note You can ask that in the Physics forum. (No, they are the same size as all other fundamental particles) Thank you, my science lesson wasn't very clear. Link to comment Share on other sites More sharing options...

Country Boy Posted December 17, 2019 Share Posted December 17, 2019 On 11/28/2019 at 11:43 AM, oliholbourns said: Well, first of all, we need to know is it a straight line? then, as druS mentioned, we may use the equation y = mx + c for a straight line. Also can I just ask if I am correct in saying that neutrinos are the smallest things in the world? I would take "line" rather than "curve" to mean "straight line". Also, do not "hijack" someone else's thread to ask an unrelated question. Start your own thread. (As Strange said, in the Physics forum, not Math.) Link to comment Share on other sites More sharing options...

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