Question

Упростите выражения:
0,9(0,4 - 1 2/3m) - 0,2(0,8 - 7 1/2m)
Найдите корень уравнения:
а) 3(0,4x + 7) - 4(0,8x - 3) = 2
б) 4,5 (7/15x + 2/9) - 0,77(8/11x - 3/7) = - 1,75

Answer 1

0.9*(0.4 - 1  2/3m) - 0.2(0.8 - 7  1/2m) = = 0.36 - 0.9 * 5/3m - 0.16 +0.2*15/2m =
= 0.2 - 0.3*5m + 0.1*15m = 0.2
==
3*(0.4x  + 7) - 4*(0.8x - 3) = 2 
1.2x + 21 - 3.2x + 12 = 2
-2x + 33 = 2
-2x = 2 - 33
-2x = -31
x = 15.5
==
4.5 * (7/15x + 2/9) - 0.77*(8/11x - 3/7) = -1.75
4.5 * 7/15x + 4.5 * 2/9 - 0.77 * 8/11x + 0.77 * 3/7 = -1.75
0.3* 7x + 0.5*2 - 0.7*8x + 0.11*3 = -1.75
2.1x + 1 - 5.6x + 0.33 = -1.75
-3.5x + 1.33 = -1.75
-3.5x = -1.75 - 1.33
-3.5x = -3.08
x = 0.88