Question

Determine a equação da reta q passa pelos pontos A(-2,1) e B(2,5) na forma geral

Answer 1

A(-2,1) e B(2,5)

m = ( yb - ya ) / ( xb - xa ) = ( 5 - 1 ) / ( 2 + 2 ) = 4/4 = 1

y - ya = m ( x - xa )

y - 1 = 1 ( x + 2 )

y - 1 = x + 2

y = x + 2 + 1

x - y + 3 = 0

Answer 2

A(-2;1)  -- x = -2 / y = 1                                    B(2;5)  -- x = 2 / y = 5


sistema de equações:

  y = ax + b   1 = -2a + b
                     5 = 4a + 1 --> b = 1 = 2a
                     5 = 2a + 1 + ( 1+ 2a )
                     5 = 4a + 1
                5 - 1 = 4a
                     4 = 4a
                     a = 1

                  b = 1 + 2a
                  b = 1 + 2(1)
                  b = 3


         f(x) = ax + b  --> f(x) = x + 3