exemplo 2 = determine a função que passa pelos pontos A = (1,5) e B = (-3,-7) [br][br] y= a.x +b ( y=5 x=1) {a.1 = a} [br] a+b= 5 [br] [br] y= a.x +b ( y= (-7) x= (-3) { (-3) . a = -3.a} [br] -3.a +b = -7 [br][br][br] a+b= 5 [color=#ff0000](x 3) [br] [/color] [br] 4 b = 8 [br] b= 8/4 [br] [color=#ff0000] b=2 [/color]a+2= 5 [br] a= 5.2 [br][color=#ff0000] a=3[/color][br] [br] [math]f[/math][color=#ff0000](x)= 3.x +2 [/color][br][br][br]