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3 years ago

Factor –7x3 + 21x2 + 3x – 9 by grouping. What is the resulting expression?

2 answers:

4 0

Take the first 2 and take out -7x2. bringing it to (-7x2)(x-3)+(3x-9)
then take out 3 on the right side.
-7x^2 (x-3)+3 (x-3)
factors to (3-7x2)(x-3)

den301095 [7]3 years ago

4 0

Step-by-step explanation:

take the first 2 and take out -7x2. bringing it to (-7x2)(x-3)+(3x-9)

then take out 3 on the right side.

-7x^2 (x-3)+3 (x-3)

factors to (3-7x2)(x-3)

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I need help with this geometry question

MArishka [77]

Answer:

Approximately 7.8 units

Step-by-step explanation:

To find the distance between any two points, we can use the distance formula:

$d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}$

From the graph, we can see that A is (0,0). Let's let this be x₁ and y₁.

B is (-5,6). Let's let this be x₂ and y₂. So, substitute:

$d=\sqrt{(-5-0)^2+(6-0)^2}$

Simplify:

$d=\sqrt{(-5)^2+(6)^2}$

Square:

$d=\sqrt{25+36}$

Add:

$d=\sqrt{61}$

Take the square root. Use a calculator:

$d\approx7.8$

So, the distance between them is about 7.8 units.

And we're done!

7 0

2 years ago

3 true? For what value of x is the equation 2-3 - +4 À B. 3 C. 9 D. -15

noname [10]

Answer:

Step-by-step explanation:

2 -3 = -1 + 4 = 3

4 0

2 years ago

Identify the law illustrated by:20x +50 is the same as 50+20x

Alisiya [41]

Answer:

The law is the Inverse law of Addition/Multiplication

Step-by-step explanation:

8 0

3 years ago

Read 2 more answers

Use undetermined coefficient to determine the solution of:y"-3y'+2y=2x+ex+2xex+4e3x

Kitty [74]

First check the characteristic solution: the characteristic equation for this DE is

r ² - 3r + 2 = (r - 2) (r - 1) = 0

with roots r = 2 and r = 1, so the characteristic solution is

y (char.) = C₁ exp(2x) + C₂ exp(x)

For the ansatz particular solution, we might first try

y (part.) = (ax + b) + (cx + d) exp(x) + e exp(3x)

where ax + b corresponds to the 2x term on the right side, (cx + d) exp(x) corresponds to (1 + 2x) exp(x), and e exp(3x) corresponds to 4 exp(3x).

However, exp(x) is already accounted for in the characteristic solution, we multiply the second group by x :

y (part.) = (ax + b) + (cx ² + dx) exp(x) + e exp(3x)

Now take the derivatives of y (part.), substitute them into the DE, and solve for the coefficients.

y' (part.) = a + (2cx + d) exp(x) + (cx ² + dx) exp(x) + 3e exp(3x)

… = a + (cx ² + (2c + d)x + d) exp(x) + 3e exp(3x)

y'' (part.) = (2cx + 2c + d) exp(x) + (cx ² + (2c + d)x + d) exp(x) + 9e exp(3x)

… = (cx ² + (4c + d)x + 2c + 2d) exp(x) + 9e exp(3x)

Substituting every relevant expression and simplifying reduces the equation to

(cx ² + (4c + d)x + 2c + 2d) exp(x) + 9e exp(3x)

… - 3 [a + (cx ² + (2c + d)x + d) exp(x) + 3e exp(3x)]

… +2 [(ax + b) + (cx ² + dx) exp(x) + e exp(3x)]

= 2x + (1 + 2x) exp(x) + 4 exp(3x)

… … …

2ax - 3a + 2b + (-2cx + 2c - d) exp(x) + 2e exp(3x)

= 2x + (1 + 2x) exp(x) + 4 exp(3x)

Then, equating coefficients of corresponding terms on both sides, we have the system of equations,

x : 2a = 2

1 : -3a + 2b = 0

exp(x) : 2c - d = 1

x exp(x) : -2c = 2

exp(3x) : 2e = 4

Solving the system gives

a = 1, b = 3/2, c = -1, d = -3, e = 2

Then the general solution to the DE is

y(x) = C₁ exp(2x) + C₂ exp(x) + x + 3/2 - (x ² + 3x) exp(x) + 2 exp(3x)

4 0

2 years ago

Help please!! Quick

Finger [1]

Step-by-step explanation:

Solve for a:

Step 1: Multiply both sides by b.

b=a

Step 2: Flip the equation.

a=b

---------------------------

Solve for b:

Step 1: Multiply both sides by b.

b=a

4 0

3 years ago