You first simplify the expression using PEMDAS
-2x^3-10x^2+2x^3-10x^2+x
then combine like terms,
(-2x^3+2x^3), (-10x^2-10x^2), x
cancels out^
so the answer would be -20x^2+x

3 0

3 years ago

Vertex form of y=x^2-4x-9

Scrat [10]

Complete the square
first isolate x terms
y=(x^2-4x)-9
complete square inside (take 1/2 of square of b )
-4/2=-2, (-2)^2=4
add 4-4 inside
y=(x^2-4x+4-4)-9
complete the square
y=((x-2)^2-4)-9
y=(x-2)^2-4-9
y=(x-2)^2-13

3 0

3 years ago

The sum of the first n consecutive even numbers can be found using S=n2+n, where n≥2. What is the value of n when the sum is 42?

lawyer [7]

Answer:

C. 6

Step-by-step explanation:

Given

S = n² + n
S = 42, n = ?

Substitute and solve for n:

42 = n² + n
n² + 2*1/2n + 1/4 = 42.25
(n + 0.5)² = 42.25
n + 0.5 = √42.25
n + 0.5 = 6.5
n = 6

Correct option is C

5 0

2 years ago

Read 2 more answers

Last year, 350 people come to see a spring concert at REL. The cost per ticket was $5.00. The orchestra committee wants to incre

Anit [1.1K]

Let 0.25x is the price increase. Therefore, the number of attendees will be 350-10x and the revenue R=(350-10x)*(5+0.25x)=1750+37.5x-2.5x^2. This parabola has maximum at x=10, meaning the price=7.5

6 0

3 years ago

Read 2 more answers