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3 years ago

Find the quotient when x2 + 10x + 21 is divided by x + 7

Mathematics

1 answer:

Alja [10]3 years ago

5 0

Answer:

The quotient is $x+3$

Step-by-step explanation:

We first use the remainder theorem to determine whether $x+7$ is divisible by

$x^2+10x+21$ :

$(-7)^2+10(-7)+21\\ = 49 - 70+21 = 0$

the remainder is zero which means $x^2+10x+21$ is divisible by $x+7$ .

Now, we could do polynomial long division to find the quotient, but in this case, it turns out that guessing is easier.

$x^2+10x+21$

is factored as

$x^2+10x+21 = (x+7)(x+3)$

which means

$\dfrac{x^2+10x+21}{x+7} =(x+3)$

which means the quotient is $x+3.$

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Dmitri wants to cover the top and sides of the box shown with glass tiles that are 5mm square. How many tiles does he need? ( Th

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Answer:

372

Step-by-step explanation:

We are given that the dimensions of the box are,

Length = 15 cm, Width = 20 cm and Height = 9 cm.

We know that the box represents a cuboid.

Since, surface area of a cuboid = L×W + 2×L×H + 2×W×H

Thus, the surface area of the box = 15×20 + 2×15×9 + 2×20×9

i.e. Surface area = 300 + 270 + 360

i.e. Surface area = 930.

Thus, the surface area of the box is 930 cm² i.e. 9300 mm².

Further, the sides of the tiles are 5 mm and the tile represents a square.

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Hence, Dmitri requires 372 tiles to cover the box.

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3 years ago

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4 years ago

A shopper buys 3 notebooks for $5 each. The percent sales tax is 8%. How much is the total sale?

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Step-by-step explanation:

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You choose a marble at random from a bag containing 8 brown marbles 6 yellow marbles and one purple marble. You replace the marb

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3 years ago

If -y-2x^3=Y^2 then find D^2y/dx^2 at the point (-1,-2) in simplest form

algol13

Answer:

$\frac{d^2y}{dx^2} = \frac{-4}{3}$

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Algebra I

Factoring

Calculus

Implicit Differentiation

The derivative of a constant is equal to 0

Basic Power Rule:

f(x) = cxⁿ
f’(x) = c·nxⁿ⁻¹

Product Rule: $\frac{d}{dx} [f(x)g(x)]=f'(x)g(x) + g'(x)f(x)$

Chain Rule: $\frac{d}{dx}[f(g(x))] =f'(g(x)) \cdot g'(x)$

Quotient Rule: $\frac{d}{dx} [\frac{f(x)}{g(x)} ]=\frac{g(x)f'(x)-g'(x)f(x)}{g^2(x)}$

Step-by-step explanation:

Step 1: Define

-y - 2x³ = y²

Rate of change of tangent line at point (-1, -2)

Step 2: Differentiate Pt. 1

Find 1st Derivative

Implicit Differentiation [Basic Power Rule]: $-y'-6x^2=2yy'$
[Algebra] Isolate y' terms: $-6x^2=2yy'+y'$
[Algebra] Factor y': $-6x^2=y'(2y+1)$
[Algebra] Isolate y': $\frac{-6x^2}{(2y+1)}=y'$
[Algebra] Rewrite: $y' = \frac{-6x^2}{(2y+1)}$

Step 3: Differentiate Pt. 2

Find 2nd Derivative

Differentiate [Quotient Rule/Basic Power Rule]: $y'' = \frac{-12x(2y+1)+6x^2(2y')}{(2y+1)^2}$
[Derivative] Simplify: $y'' = \frac{-24xy-12x+12x^2y'}{(2y+1)^2}$
[Derivative] Back-Substitute y': $y'' = \frac{-24xy-12x+12x^2(\frac{-6x^2}{2y+1} )}{(2y+1)^2}$
[Derivative] Simplify: $y'' = \frac{-24xy-12x-\frac{72x^4}{2y+1} }{(2y+1)^2}$

Step 4: Find Slope at Given Point

[Algebra] Substitute in x and y: $y''(-1,-2) = \frac{-24(-1)(-2)-12(-1)-\frac{72(-1)^4}{2(-2)+1} }{(2(-2)+1)^2}$
[Pre-Algebra] Exponents: $y''(-1,-2) = \frac{-24(-1)(-2)-12(-1)-\frac{72(1)}{2(-2)+1} }{(2(-2)+1)^2}$
[Pre-Algebra] Multiply: $y''(-1,-2) = \frac{-48+12-\frac{72}{-4+1} }{(-4+1)^2}$
[Pre-Algebra] Add: $y''(-1,-2) = \frac{-36-\frac{72}{-3} }{(-3)^2}$
[Pre-Algebra] Exponents: $y''(-1,-2) = \frac{-36-\frac{72}{-3} }{9}$
[Pre-Algebra] Divide: $y''(-1,-2) = \frac{-36+24 }{9}$
[Pre-Algebra] Add: $y''(-1,-2) = \frac{-12}{9}$
[Pre-Algebra] Simplify: $y''(-1,-2) = \frac{-4}{3}$

6 0

3 years ago