Answer:
Step 4
Step-by-step explanation:
Given: Steps used by Shelly to evaluate the expression
To find: step that includes Shelly's mistake
Solution:
According to PEMDAS,
P denotes Parentheses
E denotes Exponents
M denotes Multiplication
D denotes Division
A denotes Addition
S denotes subtraction
Step 3 is 
and step 4 is 
In step 4, first subtraction operation has been applied before the division operation.
There is a mistake in step 4 as according to PEMDAS, first -20 should be divided by 5 then 1 should be subtracted from the resultant number.
Answer:
Step-by-step explanation:
Let x represent the number of stamps from Europe.
Let y represent the number of stamps from Africa.
Let z represent the number of stamps from Asia.
She has 47 stamps in all. This means that
x + y + z = 47 - - - - - - - - - - - 1
The number of African stamps is 2 times the number of Asian stamps. This means that
y = 2z
She has 20 stamps from Europe. Therefore, substituting x = 20 and y = 2z into equation 1, it becomes
20 + 2z + z = 47
3z = 47 - 20 = 27
z = 27/3 = 9
y = 2z = 2 × 9
y = 18
She has 20 stamps from Europe, 18 stamps from Africa and 9 stamps Asia.
Two ways ∴
Fraction: 1 12/100
Decimal: 1.12
Hence the value of the expression above are as listed below
<em>f(6+4) = 25</em>
<em>f(6)+f(4) = 20</em>
<em>f(6-4) = 1</em>
<em>f(6)-f(4) = 6</em>
<em>f(6*4) = 67</em>
<em>f(6)*f(4) = 91</em>
<h3>Functions and values</h3>
Given the expression below f(x) = 3x - 5
f(6+4) = f(10) =3(10) - 5
f(6+4) = 25
f(6) = 3(6) - 5
f(6) = 18 - 5 = 13
f(4) = 3(4) - 5
f(4) = 7
f(6)+f(4) = 13+7
f(6)+f(4) = 20
f(6-4) = f(2) =3(2) - 5
f(6-4) = 1
f(6) = 3(6) - 5
f(6) = 18 - 5 = 13
f(4) = 3(4) - 5
f(4) = 7
f(6)-f(4) = 13-7
f(6)-f(4) = 6
f(6*4) = f(24) =3(24) - 5
f(6*4) = 67
f(6) = 3(6) - 5
f(6) = 18 - 5 = 13
f(4) = 3(4) - 5
f(4) = 7
f(6)*f(4) = 13*7
f(6)*f(4) = 91
Learn more on function and values here: brainly.com/question/2284360
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Raymond's stamp collection ➞x
Alice′s stamp collection➞75%x
75%x-40%×75%x+140=x-20%x
75%x-30%x+140=80%x
45%x+140=80%x
140=80%x-45%x
x=400
Raymond′s stamp collection ➞400
Alice′s stamp collection➞300
Alice sold 300×40%=120
Answer:120
