Question

A rectangle has sides measuring (2x + 7) units and (5x + 9) units.

Part A: What is the expression that represents the area of the rectangle? Show your work to receive full credit. (4 points)

Part B: What are the degree and classification of the expression obtained in Part A? (3 points)

Part C: How does Part A demonstrate the closure property for polynomials? (3 points)
Can someone help me?

Answer 1

??

Answer 2

@zepdrix

Answer 3

help

Answer 4

PLS

Answer 5

@freckles

Answer 6

what is the formula for the area of a rectangle?

Answer 7

yay phi

Answer 8

its length times the width so so assuming (2x + 7) is the length and (5x + 9) is the width, the expression would be A=(2x + 7)(5x + 9)

Answer 9

i got that for part A

Answer 10

they probably want you to expand it (FOIL if you learned that)

Answer 11

ive never learned that,no

Answer 12

did you learn how to multiply two binomials
?

Answer 13

yes i think so

Answer 14

want me to?

Answer 15

FOIL is to remember
First 2x*5x
Outer 2x*9
Inner 7*5x
Last 7*9

or
10x^2 + 18x+35x+63
and finally
10x^2 +53x+63

Answer 16

yea thats what i got

Answer 17

is that part of Part A?

Answer 18

yes, that is part A. (They want you to show your work... I assume you did)

Answer 19

yay i got part a, so can you help with part B?

Answer 20

Degree is the biggest exponent
classification is polynomial

Answer 21

so first degree binomial?

Answer 22

is that right?

Answer 23

\[ 10x^2 +53x+63 \]

what is the biggest exponent (little number in the upper right)

Answer 24

oops, 2nd degree

Answer 25

trinomial

Answer 26

i was looking at the the problem, not the solution for A=(2x + 7)(5x + 9) =10x^2 +53x+63

Answer 27

yes. all the suffices bi, tri, quad are Latin for 2, 3, 4
It helps to know your Latin

FYI, the expression
(2x + 7)(5x + 9)

even if not multiplied out, is 2nd degree
(or "quadratic" )

Answer 28

though we could not really call it trinomial if it's not multiplied out.

Answer 29

so what do we call it

Answer 30

part C is the same answer as the other problem, except use multiply instead of add or subtract.

Answer 31

You posted the answers: 2nd degree, trinomial

Answer 32

so for part c its (10x^2)(53x)(63) ?

Answer 33

for part B, you might want to also call it quadratic (just in case that is what they are expecting)

for part C, the idea is
if you multiply two polynomials, the answer will be a polynomial
in part A, you do that, and the answer was a polynomial

Answer 34

do i put that for part c?

Answer 35

in your own words.

Answer 36

ok thankyou! Can you check my answers from the other question??

Answer 37

Side 1: 3x2 − 4x − 1
Side 2: 4x − x2 + 5

The perimeter of the triangle is 5x3 − 2x2 + 3x − 8.

Part A: What is the total length of the two sides, 1 and 2, of the triangle? (4 points)

Part B: What is the length of the third side of the triangle? (4 points)

Part C: Do the answers for Part A and Part B show that the polynomials are closed under addition and subtraction? Justify your answer. (2 points)

Part A: The total length is 3x^2-x^2,which makes 2x^2+4
Part B: 4-12=-8
Part C:Part a and b both started with polynomials, and had a polynomial as an answer. So its showing that polynomials are closed under subtraction/addition.

Answer 38

Part A you say
***The total length is 3x^2-x^2***
that leaves out quite a bit.

if you add two polynomials, you have to put in the entire polynomial , not just the cute terms you like

Answer 39

3x2 − 4x − 1
+
4x − x2 + 5

Answer 40

so do i say "3x2 − 4x − 1+4x − x2 + 5=3x^2-x^2" ??

Answer 41

the left side is good. the right side should be the "simplified" version
for example you have 3 x^2 terms take away 1 x^2 term
I would combine those to get just 2x^2 (not "3x^2-x^2" because that is not simplified)
then do -4x + 4x (easy I hope?!)
then do -1+5

Answer 42

2x2+4

Answer 43

yes. You had the correct answer, but how you got the answer looked dubious.

Answer 44

ooh okay

Answer 45

Part B
I thought we did this. perimeter - (two sides) = 3rd side
you should be showing polynomial (perimeter) - polynomial (from part A) = polynomial (answer)

Answer 46

You got the answer in the other post.

Answer 47

ill look back at it brb

Answer 48

3x2−4x−1+4x−x2+5=2x^2+4 ?

Answer 49

@phi

Answer 50

no wait thats A 5x3−4x2+3x−12 ?

Answer 51

first write down the polynomial for the perimeter
then minus sign
then (in parens) the polynomial from part A

Answer 52

then =
and finally the answer 5x3−4x2+3x−12

Answer 53

5x3 − 2x2 + 3x − 8-(2x^2+4)= 5x3−4x2+3x−12?

Answer 54

yes

Answer 55

yaay thanks

Answer 56

part C is ok

Answer 57

good job. But if concentrate , it would go faster. We had to do that question twice.

Answer 58

okay thankyou