hey im stuck on this one question. its maths c1. Its got to be in 2moz.

1. The P(x,y) lies on the straight line joiningA(3,0)andB (5,6). Find the expressions for the gradients of AP and PB. Hence show that y=3x-9

thanks.

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- Sep 22nd 2008, 12:57 PMmitchoboya coordinate geometry help
hey im stuck on this one question. its maths c1. Its got to be in 2moz.

1. The P(x,y) lies on the straight line joining**A(3,0)**and**B (5,6)**. Find the expressions for the gradients of AP and PB. Hence show that y=3x-9

thanks.

- Sep 22nd 2008, 01:08 PMicemanfan
The slope of AP is $\displaystyle \frac{y - 0}{x - 3}$

and the slope of BP is $\displaystyle \frac{y - 6}{x - 5}$.

Since both AP and BP are segments of the same line, their slopes are equal. Equating the two expressions for the slope should give you the equation of the line. - Sep 22nd 2008, 01:12 PMmitchoboy
- Sep 22nd 2008, 01:19 PMicemanfan
The formula to calculate slope between two points $\displaystyle (x_1, y_1)$ and $\displaystyle (x_2, y_2)$ is $\displaystyle \frac{y_2 - y_1}{x_2 - x_1}$. All I did was to substitute the values for that formula from (3, 0) and (x, y) for the first slope and from (5, 6) and (x, y) for the second slope.

- Sep 22nd 2008, 01:31 PMmitchoboy
thanks so much i get it now lol