Wzory kartezjanskie. Zle mi wychodza 2 przykłady, wiec prosze o pomoc. Y-y1=[ ( y2-y1)/( x2-x1)] * ( x-x1) Napisz rownanie prostej AB, gdy A=(2, pierwiastekz dwoch) B= ( - pierwiastek z dwoch, 2) I drugi przyklad A=( 5/7, 2/3), B=( - 9/7, - 7/3)

Jest wzór, wystarczy odpowiednio podstawić i uważać na znaki :) [latex]A= (2, sqrt{2}) \ B=(- sqrt{2}, 2) \ \ y- y_{1} = frac{y_{2}-y_{1}}{x_{2}-x_{1}} *(x-x_{1}) \ \ y- y_{A} = frac{y_{B}-y_{A}}{x_{B}-x_{A}} *(x-x_{A}) \ \ y- sqrt{2} = frac{2-sqrt{2}}{-sqrt{2}-2} *(x-2) \ \ (y- sqrt{2}) (-sqrt{2}-2) = (2-sqrt{2})*(x-2) \ \ -sqrt{2}y-2y+sqrt{2}*sqrt{2}+2sqrt{2} = 2x-4-sqrt{2}x+2sqrt{2} [/latex] [latex]-sqrt{2}y-2y + 2 +2sqrt{2} = 2x-sqrt{2}x-4+2sqrt{2} \ \ (-sqrt{2}-2)y = 2x-sqrt{2}x-4+2sqrt{2}-2-2sqrt{2} \ \ (-sqrt{2}-2)y = (2-sqrt{2})x - 6 \ \ y = frac{(2-sqrt{2})x - 6}{-sqrt{2}-2} \ \ [/latex] [latex]y= frac{2-sqrt{2}}{-sqrt{2}-2} x - frac{6}{-sqrt{2}-2} \ \ y= frac{2-sqrt{2}}{-(sqrt{2}+2)} x - frac{6}{-(sqrt{2}+2)} \ \ y= -frac{2-sqrt{2}}{(sqrt{2}+2)} x + frac{6}{(sqrt{2}+2)} \ \ y= frac{-(2-sqrt{2})}{(sqrt{2}+2)} x + frac{6( sqrt{2}-2) }{(sqrt{2}+2)( sqrt{2}-2)} \ \ y= frac{(sqrt{2}-2)}{(sqrt{2}+2)} x + frac{6 sqrt{2}-12 }{2-4} [/latex] [latex]y= frac{(sqrt{2}-2)(sqrt{2}-2)}{(sqrt{2}+2)(sqrt{2}-2)} x + frac{6 sqrt{2}-12 }{-2} \ \ y= frac{(sqrt{2}) ^{2}-2* sqrt{2}*2+2 ^{2} }{2-4} x + (-3 sqrt{2} +6) \ \ y= frac{2-4sqrt{2}+4 }{-2} x -3 sqrt{2} +6[/latex] [latex]y= frac{6-4sqrt{2} }{-2} x -3 sqrt{2} +6 \ \ (-3+2 sqrt{2} )x-3 sqrt{2} +6 [/latex]