Question

1\4 (5х-16)- 1\2 (3у-8) ; х=2 2\5, у=6

Answer 1

1/4 = 25/100 = 0,25 - доп.множ.25

1/2 = 5/10 = 0,5 - доп.множ. 5

2/5 = 4/10 = 0,4 - доп.множ. 2

- - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Раскроем скобки и приведём подобные слагаемые:

0,25(5х - 16) - 0,5(3у - 8) =

= 0,25 · 5х - 0,25 · 16 - 0,5 · 3у - 0,5 · (-8) =

= 1,25х - 4 - 1,5у + 4 = 1,25х - 1,5у + (4 - 4) =

= 1,25х - 1,5у

если х = 2,4; у = 6

= 1,25 · 2,4 - 1,5 · 6 = 3 - 9 = - 6

Ответ: (-6).

Answer 2

To evaluate the expression 1/4(5x-16) - 1/2(3y-8) with x = 2 2/5 and y = 6, we'll substitute the values of x and y into the expression and then perform the arithmetic.

Step 1: Substitute the values of x and y into the expression: 1/4(5x - 16) - 1/2(3y - 8)

Replacing x with 2 2/5: 1/4(5 * 2 2/5 - 16) - 1/2(3y - 8)

Simplify x: 1/4(5 * 12/5 - 16) - 1/2(3y - 8)

Step 2: Simplify the expression within parentheses: 1/4(10 - 16) - 1/2(3y - 8)

Step 3: Perform the arithmetic within parentheses: 1/4(-6) - 1/2(3y - 8)

Step 4: Further simplify: -6/4 - 1/2(3y - 8)

Step 5: Perform the multiplication outside the parentheses: -3/2 - 1/2(3y - 8)

Step 6: Distribute the -1/2 through the parentheses: -3/2 - 3/2y + 4

Step 7: Combine like terms: -3/2y + 5/2

Now, we have the final expression: -3/2y + 5/2

Let's find the result for y = 6: -3/2(6) + 5/2 -9 + 5/2 -9 + 2.5 -6.5

So, when x = 2 2/5 and y = 6, the expression evaluates to -6.5.