Question

раскройте скобки и найдите значение выражения: а)-(а+2,1b)+(3,8а-1,9b) б) 3 1/3(0,3у-0,6)-1 1/4(0,8-1,6у) а) (1,2а+2,4b)-(4,3а+b) б) -1 3/7(1,4-0,7у)+0,6(1 2/3-5у)

Answer 1

A) -(a + 2,1b) + (3,8a - 1,9b) = -a - 2,1b + 3,8a - 1,9b = 2,8a - 4b
б) 3 1/3(0,3y - 0,6) - 1 1/4(0,8 - 1,6y) = 10/3 * 3/10y - 10/3 * 6/10 - 5/4 * 8/10 + 5/4 * 16/10y = y - 2 - 1 + 2y = 3y - 3 = 3(y - 1)

а) (1,2a + 2,4b) - (4,3a + b) = 1,2a + 2,4b - 4,3a - b = 1,4b -  3,1a
б) -1, 3/7(1,4 - 0,7y) + 0,6(1 2/3 - 5y) = -11/7 * 14/10 + 11/7 * 7/10y + 6/10 * 5/3 - 6/10 * 5/1y = -22/10 + 11/10y + 1 - 3y = -2,2 + 1,1y + 1 - 3y = -1,2 - 1,9y

Answer 2

а)

а)-(а+2,1b)+(3,8а-1,9b) = а - а - 2,1b + 3,8а - 1,9b

= (а + 3,8а) - (а + 2,1b + 1,9b)

= 4,8а - 4,0b

б)

3 1/3(0,3у-0,6)-1 1/4(0,8-1,6у) = 10/3(0,3у-0,6) - 5/4(0,8-1,6у)

= 10/3 * 0,3у - 10/3 * 0,6 - 5/4 * 0,8 + 5/4 * 1,6у

= 1,0у - 2,5 - 1,0 + 2,0у

= 3,0у - 3,5

а)

(1,2а+2,4b)-(4,3а+b) = 1,2а + 2,4b - 4,3а - b

= (1,2а - 4,3а) + (2,4b - b)

= -3,1а + 1,4b

б)

-1 3/7(1,4-0,7у)+0,6(1 2/3-5у) = -10/7(1,4 - 0,7у) + 3/5(5у - 1/3)

= -10/7 * 1,4 + 10/7 * 0,7у + 3/5 * 5у - 3/5 * 1/3

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2 + 2/5у - 1/5

= -2