Answer:
A.16–i is correct.
Step-by-step explanation:
(4+i)(4–i). [(a+b)(a–b)=(a²–b²)]
(4²–i²)=16–i
I hope this answer is correct so please vote my answer
6 :)
no. of books: 1 2 3 4
combinations: 12, 13, 14, 23, 24, and 34
Answer:
Equation: 
Solve for n: n = 112
Step-by-step explanation:
To first set up the equation, you need to look at the verbal description and translate into numbers and operations:
'three fourths a number' = 
'plus 8' = + 8
'is' =
'20 less' = - 20
'the number' = n
Put the expressions together:
'three fourths a number plus 8': 
'20 less than the number': n - 20
Set them equal to each other and solve:
Add 20 to both sides: 
Subtract 
from both sides: 
Multiply both sides by 
: 
Solve for n: n = 112
Substitution is where we first Isolate one of the unknowns, express it in terms of the other unknown, and replace the isolated unknown with the other unknown in another equation. So that each time we only need to deal with one unknown. I think you'll get a better idea here:
First name these 2 equations with 1 and 2.
4x + 5y = 7 (1)
y = 3x + 9 (2)
Since y is already isolated in (2), so we can skip the isolation step and continue to substitute.
Substitute (2) into (1).
4x + 5(3x+9) = 7
Expand.
4x + 15x + 45 = 7
Group.
19x + 45 = 7
Shift +45 to the other side and turn it into -45.
19x = 7 - 45
19x = -38
Shift x19 to the other side, turn it into /19.
X = - 38/19
X = - 2
Now we solved x already, we can just substitute x= - 2 back to equation (2).
y = 3(-2) + 9
y = - 6 + 9
y = 3
So, the answers are
x = - 2
y = 3
Answer:956012
Step-by-step explanation:
