Question

scrieti ecuatia dreptei determinate de punctele A(5;2), B(1;-4) ....formula?

Answer 1

determinant din : 5  2  1
                            1  -4  1       =o <=> -20+y+2x+4x-5y-2=0 <=>6x-4y-22=0 <=>
                             x  y  1                <=>y=$\frac{6x-22}{4}$

Answer 2

Sunt doua metode

1)Metoda 1 (clasa 10)

[tex] \frac{x-x1}{x2-x1}= \frac{y-y1}{y2-y1} [/tex]

[tex] \frac{x-5}{1-5}= \frac{y-2}{-4-2} [/tex]

[tex] \frac{x-5}{-4}= \frac{y-2}{-6} -4(y-2)=-6(x-5) -4y+8=-6x+30 -4y+8+6x-30=0 6x-4y-22=0 [/tex]

Metoda 2 (clasa 11)

[tex] \left[\begin{array}{ccc}1&1&1\\x&5&1\\y&2&-4\end{array}\right]= -20+y+2x-(5y+2-4x)=0 -20+y+2x-5y-2+4x=0 6x-4y-22=0 [/tex]