Anonymous
Anonymous asked in Education & ReferenceHomework Help · 2 months ago

How do you know which variable comes 1st in the answer? Does it matter?

When multiplying a monomial by a polynomial:

2r(3r+7q)

but the worksheet says the answer is 6r^2+14qr

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• 2 months ago

wish i was focusing in math class lmao

• 2 months ago

the formal approach is to alphabetize within each term. [I prefer your answer. Easier to see how you obtained it.}

• Anonymous
2 months ago

It doesn't matter. Do you not remember the "commutative property of multiplication," which says that q times r equals r times q in all cases?

• 2 months ago

However, the mathematical convention is to qrite the letter algebraically.

Since 'q' comes before 'r' in the alphabet you would write '14qr'

NB Terms in higher powers come first .

• David
Lv 7
2 months ago

Your answer is correct but the worksheet has only put the variables in alphabetical order.

• 2 months ago

alphabetically q is before r

so by convention it is written as 14qr

But note that 14qr = 14rq

• Elaine
Lv 7
2 months ago

In algebra qr = rq The worksheet has listed the variables (letters) in the same order as they appear in the English alphabet

Think of Arithmetic: 2 X 3 = 3 X 2

• Anonymous
2 months ago

Order does not matter, operationally speaking. By means of the commutative axiom, order remains same for multiplication in this way:

a * b = b * a = ab = ba, equals same quantity.

However, arrangement is used for clarity. 2r distributed to 7q is better expressed as 14qr since it is (2r * 7q), hence the q was with 7 before the r.