Question

вычислите наиболее удобным способом

Answer 1

1)

(6,25 * 3,6 - 6,25 * 1,2) / (1,2 * 2,5) =
= (6,25 * 1,2 * 3 - 6,25 * 1,2) / (1,2 * 2,5) = 
= 6,25*1,2*(3-1) / (1,2 * 2,5) =
= (6,25*1,2*2) / (1,2*2,5) = 
= (2,5*2,5*1,2*2) / (1,2*2,5) =
= 2,5 * 2 = 5,

2)

(-2,7*0,42*(-0,84)) / (0,6*(-0,21)*6,3) = 
= (сокращ. 2,7 и 6,3;  0,84 и 0,21;  0,42 и 06) =
= (-3*4*7) / 7 = 
= -3 * 4 = -12,

3)

(2,4*0,08 + 4,8*0,08) / (-1,8*0,04) = 
= 0,08*(2,4 + 4,8) / (-1,8*0,04) = 
= 2*0,04*7,2 / (-1,8*0,04) = 
= 2*4*1,8 / (-1,8) = 
= -2 * 4 = -8,

4)

((-1/6) * (3/7) * (-1 1/4)) / ((-1/7) * (-1 1/2) * (5/6)) = 
= ((-1/6) * (3/7) * (-5/4)) / ((-1/7) * (-3/2) * (5/6)) = 
= (1/6 * 3/7 * 5/4) * (7/1 * 2/3 * 6/5) = 
= 2/4 = 1/2