Ответ:

Объяснение:

1)40,33a-51,2a-12,19a-a=40,3a-64,39a=- 24,09a

2)-81,4b+90b-7,15b+0,45b=90,45b-88,55b=1,9b

3)(13 2/15)c – (15 1/3) c +(3,5) c –(4/5) c=

 =(197/15)c –(46/3)c+(35/10)c-(4/5)c=(394c-400c+105c-24c) /30=

 =(499c-424c) / 30 = 75c/30=2,5c

4)

(59 3/16)t + (4 1/8)t -64,25t+(3/4)t=(547/16)t+(33/8)t -64,25t+0,75t=

=34,1875t+4,125t-64,25t+0,75t=39,0625t-64,25t=-25,1875t