Question

7(0,74+0,9)-5,05-13,8                     4(0,8x- 0.25 y)-0.7( 2x-y) если x=0.2 y=0.6

Answer 1

5.18+7.9-5.05-11.07х+13.49у-1.4х+0.7у=8.03-12.47х+14.19у=8.03-(12.47*0.2)+(14.19*0.6)=8.03-2.49+8.51=14.05

Answer 2

Let's solve the given expressions step by step.

Expression 1: 7(0.74 + 0.9) - 5.05 - 13.8

First, let's calculate the values within the parentheses: 0.74 + 0.9 = 1.64

Now substitute the value back into the expression: 7(1.64) - 5.05 - 13.8

Next, multiply 7 by 1.64: 7 * 1.64 = 11.48

Substituting the value back: 11.48 - 5.05 - 13.8

Now, subtract the remaining numbers: 11.48 - 5.05 - 13.8 = -7.37

So, the value of the expression is -7.37.

Expression 2: 4(0.8x - 0.25y) - 0.7(2x - y)

Given x = 0.2 and y = 0.6, substitute these values into the expression:

4(0.8 * 0.2 - 0.25 * 0.6) - 0.7(2 * 0.2 - 0.6)

Simplify within the parentheses:

4(0.16 - 0.15) - 0.7(0.4 - 0.6)

4(0.01) - 0.7(-0.2)

Multiply within the parentheses:

0.04 + 0.14

Combine the terms:

0.18

So, the value of the expression is 0.18.

Therefore, when x = 0.2 and y = 0.6, the first expression evaluates to -7.37, and the second expression evaluates to 0.18.