End points of diameter are (4,7) and (−2,−1). Then, equation of circle is(x−4)(x+4+(y−7)(y+1)=0 ⇒x2+y2−2x−6y−15=0 ...(i) General equation of circle is x2+y2+2gx+2fy+c=0 ...(ii) Compare Eqs. (i) and (ii), we obtain g=−1,f=−3,c=−15 Now, X-intercept is given as, AB=2√g2−c=2√1−(−19)=2√16=8 ∴AB=8