y=(4/3)•0 - 4=-4 B(0,-4)(4/3)x - 4=0,则x=3A(3,0)设C(x,0)AB=√(0-3)²+(-4-0)²=5①当AB=AC时:|x-3|=5x-3=±5∴x=8或x=-2即:C(8,0)或(-2,0)②当BC=AB时:√(x-0)²+(0+4)²=5x² + 16=25x²=9,则x=±3当x=3时,点C与A重合∴C(-3,0)