А)
√(149²-76²) √(149-76)(149+76) √(73*225) √225 15
----------------- = ------------------------------- = ----------------- = ---------- = ------
√(457²-384²) √(457-384)(457+384) √(73*841) √841 29
б)
71²-23²+94*42 (71-23)(71+23)+94*42 48*94+94*42 94*(48+42)
--------------------- = ------------------------------- = ------------------- = ----------------- =
62²-32² (62-32)(62+32) 30*94 30*94
=90/30=3
в)
√(9²*5,3²-25,2²)= √(47,7²-25,2²) =√((47,7-25,2)(47,7+25,2)) = √(22.5*72.9)=
=√(2.25*729)=1.5*27=40.5
г) решаем по частям
√(115²-15²) √(115-15)(115+15) √(100*130)
1) 0,3* --------------- = 0,3* ------------------------- = 0.3*--------------- =0.3*10=3
√130 √130 √130
√(273²-16² ) √((273-16)(273+16) ) √(257*289)
2) 1/17 *---------------- = 1/17* -------------------------- = 1/17 *----------------- =
√257 √257 √257
= (1/17)*17= 1
3) 3+1=4