<prompt> Ikiwa a, b ni nambari zisizo za kweli kama vile a2b28ab, pata thamani ya leftfracaba-bright.  <response>: Kumbuka kwamba kushotofracaba-bkulia sqrtfracab2a-b2 sqrtfraca2b22aba2b2-2ab sqrtfrac10ab6ab fracsqrt153. 