21. A binary operation is defined on set R of real numbers by:
a*b = a +b-2ab, were ben
(D) is the operation * closed on de
set R? Give a reason for you
answer.
Find the identity element of
under the operation*
(11) Determine the inverse under of
general element aR stating whidi
element has no inverse

What is the equation of a parabola y(x) that has a vertex at point (− 1/3 , 0.3) and passes through point (− 2/15 , − 1/2 ).

Dropping less than two inches per mile after emerging from the mountains, a river drains into the ocean. one day's discharge at its mouth, 5.6 trillion gallons, could supply all of country a's households for seven months. based on this statement, determine how much water an average household uses each month. assume that there are 100 million households in country a. country a uses approximately nothing gallons per household per month.

Ineed with angles and the measure of them i have abc a is 65 and b is (3x-10) and c is (2x) find the value of x