<span>ab-ac = a(b - c)
mn-m = m(n - 1)
9x- 3y = 3(3x - y)
4,5m+1,5n = 1.5(3m + n)
mnk - mn = mn(k - 1)
abc+ab</span> = ab(c + 1)
1. S = ut=13*407=5304 км/ч
2. S = ut, следовательно, t=S/u = 7200:800=9ч
<u>63 : (3 * 7) = ?</u>
1) 3 * 7 = 21
2) 63 : 21 = 3