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AS Maths co-ordinate geo help

I need help of this question
P co-ordinates (7,4) and Q (9,7) find the equation for the straight line L which passes through P and Q give your answer in the form ax+by+c=0 where a,b and c are intergers.
I understand you need the equation y-y1=m(x-x1) but I don't get how you get intergers.

Can you guys show me how you get an answer ??
Thanks

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Reply 1

C0balt

(7-4)/(9-7)=3/2
y-4=3/2(x-7)
y-4=3/2x-21/2

multiply by 2 to get integer because you wanna get rid of fraction

Reply 2

Malawasheree

It's (Y2 - Y1) / (X2 - X1) to find the gradient of two points.

For Y1 and X1 in the equation, you can sub in either P or Q. You might also want to sub in the values of the other point into the equation that you get to double-check your answer.