Question

1.
(07.01 MC)
Part A: Explain why x = 3 makes 4x − 1 ≤ 11 true but not 4x − 1 < 11. (5 points)

Part B: What value from the set {4, 5, 6, 7, 8} makes the equation 8x + 1 = 57 true? Show your work. (5 points)

Answer 1

You using flvs?

Answer 2

replace x by 3 and see what you get

4x - 1 ≤ 11
4(3) - 1 = what ?

Answer 3

i dont know

Answer 4

4 times 3 = ?

Answer 5

12

Answer 6

now subtract 1 from 12

12 - 1 = 11 right/

Answer 7

4(3) - 1 = 12 - 1 = 11

Answer 8

yes

Answer 9

so that makes it true because ≤ 11 means greater than OR equal to 11

Answer 10

now plug in x = 3 into the other inequality
4x - 1 < 11
4(3) - 1 = 11

so is 4x - 11 < 11 true or false when x = 3?

Answer 11

true

Answer 12

?? what does 4x - 1 < 11 mean in words?

Answer 13

oh sorry i meant to say false

Answer 14

< means what?

Answer 15

greater than

Answer 16

sorry I made a mistake in an earlier post
≤ means less than or equal to not greater than or equal to

Answer 17

NO < means less than

Answer 18

oh ok

Answer 19

so 4(3) - 1 = 11 when x = 3
Now is 11 less than 11?

Answer 20

yea its greater than

Answer 21

Of course not
so for x = 3, 4x- 1 <11 is false

Answer 22

k

Answer 23

Do you see why its false?

beacuse when x = 3, 4x - 1 = 11 but the inequality is 4x - 1 < 11

Answer 24

yea

Answer 25

For part B
one way to do this is to solve the equation (find what value of x fits the equation)

8x + 1 = 57


can you do that?

Answer 26

nope

Answer 27

OK well the other way is to plug in each of the numbers in the given set and see which one fits

Answer 28

8

Answer 29

try x = 4;

8*4 + 1 = 32 + 1 = 33

- we need it to work out to 57 not 33 . So 4 is not the answer.

Neither is 8

try the other numbers

Answer 30

what is 8*5 + 1
- do the multiply first then add the 1

Answer 31

you can do it
Multiply 8 by 5 then add 1