478 ( а,б,в,г,) помогите !!! буду очень благодарна !!!!

А)9/56-(7/15-5/12)·(3/14+1/2)=9/56-(7·4-5·5)/60·(3+7)/14=
=9/56-(28-25)/60·10/14=9/56-3/60·10/14=9/56-3·10/(60·14)=9/56-30/(60·14)=
=9/56-1/28=(9-2)/56=7/56=1/8;
б)(2/3+7/8-5/6)·(1-5/17)=(2·8+7·3 - 5·4)/24·(17-5)/17=(16+21-20)/24·12/17=
=17/24·12/17=(17·12)/(24·17)=1/2;
в)(2¹/₂)²·8/15-5/9=(5/2)²·8/15-5/9=(25·8)/(4·15)-5/9=10/3-5/9=(30-5)/9=
=25/9=2⁷/₉;
г)(2¹/₃·1²/₇)³·2/9=(4/3·9/7)²·2/9=16/9·81/49·2/9=(16·81·2)/(9·49·9)=32/49;
д)(3¹/₁₄-2⁵/₂₁)·(1/2-2,1)=(15/14-47/21)·(1/2-21/10)=(15·3-47·2)/42·(5-21)/10=
=(45-94)/42·(-16/10)=(-49)·(-16)/(42·10)=(7·8)/(6·5)=56/30=28/15=1¹³/₁₅;
е)(4¹³/₁₈-3⁷/₉)·(1/2-4/17)=(85/72-34/27)·(34-8)/34=(85·3-34·8)/216·26/34=
=(255-272)/216·13/17=(-17)·13/(216·17)=-13/216;