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Evaluate 3x² - 4xy + 2y² - 1 for x = - 3 and y = 5

zhannawk [14.2K]

Answer:

$3x^{2} - 4xy + 2y { }^{2} - 1 \\ 3 \times ( - 3) { }^{2} - 4 \times ( - 3) \times 5 + 2 \times 5 {}^{2} - 1 \\ (3 \times 9) - ( - 60) + 50 - 1 \\ 27 + 60 + 50 - 1 \\ 165$

8 0

8 months ago

Read 2 more answers

Elena went to a sporting goods store that was having a sale. She bought a tennis ball and 3 cans of tenis balls The tennis racke

Kazeer [188]

Answer: She will pay $52.68, including taxes

Step-by-step explanation: One can of tennis ball is $4 and there are no discount on it. Elena bought 3 cans, so:

can = 3 x 4 = 12

One tennis racket is $43 but it has a discount of 15%:

discount = 0.15 x 43 = 6.45

total racket = 43 - 6.45 = 36.55

Elena will have to pay:

pay = 12 + 36.55 = 48.55

She will also have to pay taxes, which are 8.5% over the price she paid:

pay + tax = 48.55 x 0.085 = 4.13

total to pay = 48.55 + 4.13 = 52.68

Buying 3 can of tennins ball and one racket, Elena paid $52.68, including taxes.

4 0

2 years ago

Find the area of the sector.

kicyunya [14]

Answer:

D. 158.4 km²

Step-by-step explanation:

Area of sector = θ/360 * πr²

Where,

θ = 150°

r = 11 km

Substitute

Area = 150/360 * π * 11²

Area = 158.38863 ≈ 158.4 km² (nearest tenth)

3 0

2 years ago

Complete the factorization of 3x ^ 2 - 10x + 8 3x^ 2 -10x+8=(x- Box x-4)

aniked [119]

Answer:

$3x^2-10x+8=(x-x_1)(x-x_2)=(x-2)(x-\frac{4}{3})$

Step-by-step explanation:

The general form of a quadratic polynomial is given by:

$ax^2+bx+c$ (1)

You have the following polynomial:

$3x^2-10x+8$ (2)

In order to complete the factorization you can use the quadratic formula, to obtain the roost of the polynomial. The quadratic formula is given by:

$x_{1,2}=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$ (3)

By comparing the equation (1) with the equation (2) you obtain:

a = 3

b = -10

c = 8

Then, you replace these values in the equation (3):

$x_{1,2}=\frac{-(-10)\pm \sqrt{(-10)^2-4(3)(8)}}{2(3)}\\\\x_{1,2}=\frac{10\pm2}{6}\\\\x_1=2\\\\x_2=\frac{4}{3}$

Then, the factorization of the polynomial is:

$3x^2-10x+8=(x-x_1)(x-x_2)=(x-2)(x-\frac{4}{3})$

5 0

2 years ago

A rancher wants to fence in an area of 1000000 square feet in a rectangular field and then divide it in half with a fence down t

frosja888 [35]

The shortest length of the fence used by the rancher in a rectangular field of 1000000 square feet is 4899 ft.

<h3>What is the area of a rectangle?</h3>

The area of a rectangle is a region enclosed in four corners where two opposite sides are equal. The area of the rectangle is mathematically expressed as:

Area of a rectangle = length(x) × breath(y)

1000000 sq.ft = (x) × (y) ---- (1)

However, to determine the fencing, we have:

Length of fencing = 2x + 2y