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3 years ago

Which equations are correct

Mathematics

1 answer:

VARVARA [1.3K]3 years ago

3 0

Answer:

2nd, 3rd and 4th equations are correct.

Step-by-step explanation:

$-4x^2(2x^2+5)=-8x^4-20x^2\\\\$

is right because each term inside is multiplied by -4x square and we find the answer is right.

$-4b^3(5b^2+3)\\\\\\= -4(5)(b^3)(b^2) =-20b^6-12b^3\\$

Hence correctly done.

$-5a^4(2a^2+4)= (-5)(2)(a^4)(a^2)+(-5)(4)(a^4\\-10a^6-20a^4\\$

Correctly done.

$-6^4(4y^2+2)=-24y^8-12y^4\\= -(6)(6)(6)(6) 4y^2 -(6)(6)(6)(6) (2)$

should be the right answer.

But instead only 6 is multiplied by inner terms. Hence wrong.

I answer is wrong and others are right.

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What is the vertex of the graph of the function f(x) = x2 − 4x?

Vsevolod [243]

Answer:

(2, -4).

Step-by-step explanation:

x^2 - 4x

= (x - 2)^2 - 4.

So the vertex is at

(2, -4).

6 0

3 years ago

Read 2 more answers

Priscilla has 4.3*10^8 strands of hair on her head. Diego has 8.7*10^5 strands of hair on his head. How many more strands of hai

MrMuchimi

<h3>Answer: 4.2913 * 10^8</h3>

====================================================

Work Shown:

4.3*10^8 = 4.3 * 10^(3+5)

4.3*10^8 = 4.3 * 10^3*10^5

4.3*10^8 = 4.3*1000*10^5

4.3*10^8 = 4300*10^5

Priscilla has 4300*10^5 strands of hair while Diego has 8.7 * 10^5 strands. Subtract the values out front: 4300-8.7 = 4291.3

Then tack on the "*10^5" portion to get 4291.3*10^5

The difference in the number of strands is 4291.3*10^5

Convert this to scientific notation to get the final answer.

4291.3*10^5 = (4291.3)*10^5

4291.3*10^5 = (4.2913 * 1000)*10^5

4291.3*10^5 = 4.2913 * 1000*10^5

4291.3*10^5 = 4.2913 * 10^3*10^5

4291.3*10^5 = 4.2913 * 10^(3+5)

4291.3*10^5 = 4.2913 * 10^8

Note: The number 4.2913 * 10^8 expands out to 429,130,000 which is a little over 429 million.

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3 years ago

Felix is now six times as old as Debbie. In twelve years time Felix will be two times as old as Debbie. How old are they

Minchanka [31]

Step-by-step explanation:

let debbie be x years

let felix be 6x years

in 12 years felix will be 2x older than debbie

do the calc

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3 years ago

The price of a watch was increased by 20% to £144. What was the price before the increase

MAXImum [283]

Answer:

120 pounds

Step-by-step explanation:

Since the new cost is 144 pounds and this is 20% more, this is 120% of the original price. Remember 100+20 = 120. To find the original price set up a proportion with these values:

Solve for the original price by cross multiplying numerator with denominator.

x(120) = 144(100)

120x = 14400

x= 120 pounds

3 0

3 years ago

Avani wrote the linear equation y = 5 x + 4. Then, she wrote the equation of the line that is perpendicular to y = 5 x + 4 and t

Margarita [4]

Avani wrote the linear equation y = 5x + 4. Then, she wrote the equation of the line that is perpendicular to y = 5x+ 4 and that passes through (15,–2). If her new equation is in the form $y-\frac{1}{5}x+b$ , what is the value of b?

$\bf y=mx+b$

m is the slope
b is the y-intercept

The equation of a line that is perpendicular to another line always has the opposite reciprocal slope. In the original equation, the slope is 5. The opposite of 5, which refers to the sign, is -5. The reciprocal of -5 is -1/5. That means the slope of the new line is -1/5.

The perpendicular line: