Question

The work of a student to find the dimensions of a rectangle of area 6 + 8x and width 2 is shown below:

Step 1: 6 + 8x
Step 2: 2(4) + 2(6x)
Step 3: 2(4 + 6x)
Step 4: Dimensions of the rectangle are 2 and 4 + 6x

In which step did the student first make an error and what is the correct step?
Step 3; 2 + (4 + 6x) Step 3; 2 + (4 ⋅ 6x) Step 2; 2(4) + 2(4x) Step 2; 2(3) + 2(4x)

Answer 1

@UsukiDoll

Answer 2

let me read and catch up on that for a bit.

Answer 3

k

Answer 4

@DeltaForce

Answer 5

@DarkMoonZ

Answer 6

@Donblue

Answer 7

@unicwaan

Answer 8

@shinebrightlikeadimon

Answer 9

whoa... please do not mass tag. It's a form of spam on OS
and anyway
A = L X W
area of the rectangle = length x width

Answer 10

oh sry

Answer 11

do u understand the question????

Answer 12

so given area
6+8x
width
2
6+8x =2L

Answer 13

hmmm... perimeter is
P=2L+2W but it's not asking that..

Answer 14

it wants to know where she went wrong

Answer 15

area -> 6+8x
width -> 2
length -> ?
area = width x length
6+8x=2L
and supposedly to get length by itself we have to divide 2
3+4x=L

Answer 16

so
6+8x = 2(3+4x)
ok the width is 2 and the length is 3+4x. student messed up really early.

Answer 17

ya

Answer 18

looks like she is going backwards

step 1 we have
6+8x
then
split these two numbers up
2(3)+2(4x)
the 2 is yanked out
2(3+4x)
yay!
6x+8 = 2(3+4x)
6x+8=6+8x

Answer 19

Step 2; 2(3) + 2(4x) <- this is the correct one. It took a while because I haven't done this in years, but with patience we got what we need ^^

Answer 20

yup

Answer 21

an that part works because
I was using A =WL
6+8x=2L and solved for L
which was 3+4x=L
so by looking at her work carefully I see that she did it differently by not using the formula A =L X W
so she split 6 and 8 and factored out a 2 but in her original step 2 she wrote the wrong number

Answer 22

sorry stuck in reply mode.

Answer 23

so step 2 was the wrong one

Answer 24

oh yeah
we can prove that with ease
given that A = 6x+8 and width 2

on her step 2 she had

Step 2: 2(4) + 2(6x)

which doesn't make sense
that 8+12x which is the wrong area

Answer 25

Step 2; 2(4) + 2(4x)

Step 2; 2(3) + 2(4x)
which one is right

Answer 26

._. the second one

Answer 27

distribute the 2
on 2(4)+2(4x)
we got the wrong number with x again
8+8x
we were NOT given that

Answer 28

2(3) + 2(4x)
that's
6+8x which is the area we were given in the first place

Answer 29

sorry stuck in reply mode.. don't know what's going on ^^

Answer 30

but recommendation to student
use the formula A = L X W it's easier

Answer 31

thx soo much

Answer 32

i will ask more questions later will u be here

Answer 33

in like 10 min

Answer 34

depends. It's the middle of the night where I live...
yeah sure. It also depends on the question too...

Answer 35

easier than this one

Answer 36

where do u live???

Answer 37

what country

Answer 38

Personal information shouldn't be discussed on OpenStudy... Code of Conduct.

Answer 39

ohh sorry didnt know

Answer 40

sorry, i was late to reply to this @3.14192653589