Упрастите и вычислите -5(0,6с-1,2)-1,5с-3 при с =-4/9

To simplify and calculate the expression, let's substitute the value of c:

c = -4/9

Now, let's substitute c back into the expression:

-5(0.6c - 1.2) - 1.5c - 3

= -5(0.6(-4/9) - 1.2) - 1.5(-4/9) - 3

= -5(-2.4/9 - 1.2) + 6/3 - 3

= -5(-2.4/9 - 1.2) + 2 - 3

Next, let's simplify the expression inside the parentheses:

-2.4/9 - 1.2 = -2.4/9 - (1.2 * 9/9)

= -2.4/9 - 10.8/9

= (-2.4 - 10.8)/9

= -13.2/9

Now, substitute this value back into the main expression:

-5(-13.2/9) + 2 - 3

= 66/9 + 2 - 3

= 22/3 + 2 - 3

Now, let's get a common denominator for the fractions:

= (22 + 6)/3 - 3

= 28/3 - 3

Finally, subtract the fractions:

= (28 - 9)/3

= 19/3

So, the simplification of the expression -5(0.6с - 1.2) - 1.5с - 3, when c = -4/9, is 19/3.