Question

7*(2,3+0,8)+1,9х при х=0,4. 0,9*(6х+5)-3,2 при х =12. 2,5*(3х+0,4)-5,1 при х=8

Answer 1

1) 7*(2,3+0,8)+1,9*0,4=
=8*3,1+1,9*0,4=
=24,8+0,76=
=25,56
2) 0,9*(6*12+5)-3,2=
=0,9*77-3,2=
=69,3-3,2=
=66,1
3) 2,5*(3*8+0,4)-5,1=
=2,5*24,4-5,1=55,9

Answer 2

Let's calculate the expressions step by step using the given values for x.

Expression 1: 7*(2.3+0.8)+1.9*x, where x = 0.4

First, let's simplify the expression inside the parentheses: 2.3 + 0.8 = 3.1

Now substitute the value of x into the expression: 7 * 3.1 + 1.9 * 0.4

Multiply: 21.7 + 0.76

The result is 22.46.

Expression 2: 0.9*(6*x+5)-3.2, where x = 12

Substitute the value of x into the expression: 0.9 * (6 * 12 + 5) - 3.2

Simplify: 0.9 * (72 + 5) - 3.2 0.9 * 77 - 3.2

Multiply: 69.3 - 3.2

The result is 66.1.

Expression 3: 2.5*(3*x+0.4)-5.1, where x = 8

Substitute the value of x into the expression: 2.5 * (3 * 8 + 0.4) - 5.1

Simplify: 2.5 * (24 + 0.4) - 5.1 2.5 * 24.4 - 5.1

Multiply: 61 - 5.1

The result is 55.9.

Therefore, the values of the expressions are as follows: Expression 1: 22.46 Expression 2: 66.1 Expression 3: 55.9