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# Algebra/Binary... Operation

Question
Mathematics is my favorite subject, but the following question makes me feel that mathematics is pointles and grey:
A binary operation * is defined on the set R of real numbers by a * b= a + b + ab whare a, b belongs to R
(i) calculate 5*(-2)*5
(ii) find the identity element of R under the operation *
(* symbolizes binary operation; that is how it is used in my book.)
HELP ME SOLVE IT!

Since a * b = a + b + ab, this says we only take two numbers at once.
Since the 1st two numbers are 5 and -2, take a=5 and b=-2.
This gives a*b = 5 -2 -10 = 3-10= -7.

We then use -7 and 5 as a and b.
This says that -7 * 5 = -7 + 5 - 35. = -37.

Algebra

Volunteer

#### Scott A Wilson

##### Expertise

Any algebraic question you've got. That includes question that are linear, quadratic, exponential, etc.

##### Experience

I have solved story problems, linear equations, parabolic equations. I have also solved some 3rd order equations and equations with multiple variables.

Publications
Documents at Boeing in assistance on the manufacturiing floor.

Education/Credentials
MS at math OSU in mathematics at OSU, 1986. BS at OSU in mathematical sciences (math, statistics, computer science), 1984.

Awards and Honors
Both my BS and MS degrees were given with honors.

Past/Present Clients
Students in a wide variety of areas since the 80's; over 1,000 of them have been in algebra.