Question

(4-y)-y(y+1) при y=-1/9

Answer 1

To evaluate the expression (4-y)-y(y+1) at y = -1/9, we substitute the value of y into the expression:

(4 - y) - y(y + 1)

First, let's substitute y = -1/9 into the expression:

(4 - (-1/9)) - (-1/9)(-1/9 + 1)

Simplifying further:

(4 + 1/9) - (-1/9)(8/9)

Next, let's evaluate the multiplication (-1/9)(8/9):

(-1/9)(8/9) = -8/81

Substituting this value back into the expression:

(4 + 1/9) - (-8/81)

To subtract a negative number, we can change it to addition:

(4 + 1/9) + (8/81)

Now, we need to find a common denominator for 9 and 81, which is 81:

(4 * 81 + 1 * 81) / 81 + 8/81

(324 + 81) / 81 + 8/81

405 / 81 + 8/81

Combining the fractions:

(405 + 8) / 81

413 / 81

Therefore, the value of the expression (4-y)-y(y+1) at y = -1/9 is 413/81.