123. Найдите значение выражения

8 (3 - 3,5m) - 20 + 23m

при m = 2,5; 1,2; 40.

1. m=2.5

8 (3 - 3,5*2.5) - 20 + 23*2.5 = 8 (3 - 8.75) - 20 + 57.5 = 8 * (-5.75) - 20 + 57.5 = - 46-20 + 57.5 = - 8.5

2. m=1.2

8 (3 - 3,5*1.2) - 20 + 23*1.2 = 8 (3 - 4.2) - 20 + 27.6 = 8 * (-1.2) - 20 + 27.6 = - 9.6 - 20 + 27.6 = - 2

3. m=40

8 (3 - 3,5*40) - 20 + 23*40 = 8 (3 - 140) - 20 + 920 = 8 * (-137) - 20 + 920 = - 1096 - 20 + 920 = - 196

=24-28m-20+23m=-5m+4

1) если m=2,5, то - 5*2,5+4=-8,5

2) m=1,2; - 5*1,2+4=2

3) m=40; - 5*40+4=-196