10х*7х=4900
70х=4900
х=4900/70
<span>х=70 </span>
11/4+5/12×(1/3×2 1/2 - 7/8)=2,7
1/3×2 1/2= 1/3×5/2=5/6
5/6 - 7/8=20/24-21/24= -1/24
5/12×(-1/24)= - 5/288
11/4+(-5/288)=792/288-5/288=787/288=
=2,7
5/12, 4/15, 3/10
12=2*2*3
15=3*5
10=2*5
НОК=2*2*3*5=60
25/60, 16/60, 18/60