Answer:
The fourth term of the expansion is -220 * x^9 * y^3
Step-by-step explanation:
Question:
Find the fourth term in (x-y)^12
Solution:
Notation: "n choose k", or combination of k objects from n objects,
C(n,k) = n! / ( k! (n-k)! )
For example, C(12,4) = 12! / (4! 8!) = 495
Using the binomial expansion formula
(a+b)^n
= C(n,0)a^n + C(n,1)a^(n-1)b + C(n,2)a^(n-2)b^2 + C(n,3)a^(n-3)b^3 + C(n,4)a^(n-4)b^4 +....+C(n,n)b^n
For (x-y)^12, n=12, k=3, a=x, b=-y, and the fourth term is
C(n,3)a^(n-3)b^3
=C(12,3) * x^(12-3) * (-y)^(3)
= 220*x^9*(-y)^3
= -220 * x^9 * y^3
Answer:
x>4
Step-by-step explanation:
Solving an inequality is very similar to solving an equation:
Given: 7x-6>22
Add 6 to both sides: 7x>28
Divide both side by 7: x>4
x>4 means that all x-values that are greater than 4 will work. Therefore you would write an open dot at x=4 on the number line to show that 4 isn't included, and draw an arrow going right to show all possible solutions greater than 4.
Answer:
y = (5/4)x + 6
Step-by-step explanation:
The 1st line's equation is:
● 4x + 5y = 20
Substract 4x from both sides
● 4x + 5y - 4x = 20 - 4x
● 5y = 20 -4x
● 5y = -4x + 20
Divide both sides by 5
● 5y/5 = (-4x + 20)/5
● y = (-4/5)x + 4
● y = -0.8x + 4
Let m be the slope of the second line
The lines are perpendicular so the product of their slopes equals -1
Then: m × (-0.8) = -1
● m × (-0.8)= -1
● m = -1/(-0.8)
● m = 1.25
y = 1.25x + b
b is the y-intercept of the line.
To get it replace by the coordinates of a point.
We are given that the line passes through (-4,1)
● y = 1.25x + b
● 1 = 1.25 × (-4) + b
1.25 is 5/5
● 1 = (5/4) × (-4) + b
● 1 = -5 + b
Add 5 to both sides
● 1 + 5 = -5 + b + 5
● b = 6
So the equation is
● y = (5/4)x + 6
Answer:
D. 6 1/12
Step-by-step explanation:
3 2/3= 3 8/12, 1 3/4= 1 9/12, 2/3= 8/12 || add (3 8/12+ 1 9/12+ 8/12= 4 25/12= 6 1/12)