T(t)=1340+40t+5t²=1400
5t²+40t+1340-1400=0
5t²+40t-60=0
t²+8t-12=0
D=64+48=112
t1=(-8-4√7)/2=-4-2√7-не удов усл
t2=-4+2√7≈-4+2*2,646≈3,292
5/22+2/11х=16/44
2/11х=16/44-5/22
2/11х=6/44
х=6/44разделить на 2/11=6/8=3/4
3:2 1/2+2 2/5*2 1/2 - 3 2/3 = 3 8/15
1) 3:2 1/2 = 3:5/2=3*2/5 = 6/5 = 1 1/5
2) 2 2/5*2 1/2 = 12/5*5/2=6
3) 1 1/5+6=7 1/5
4) 7 1/5 - 3 2/3 = 36/5-11/3 = 108/15-55/15 = 53/15 = 3 8/15
1)4+3=7 (к) 2) 4+7=11 Ответ: 11 вешей выстирала оля