All categories

3 years ago

Which expression is equivalent to 21 × 7?

Mathematics

1 answer:

Sergio039 [100]3 years ago

6 0

Answer:

Step-by-step explanation:

its the same thing if you multiply 3×4 and 4×3 for example

and you get the same result both times

You might be interested in

What is the product of 3a + 5 and 2a2 + 4a – 2?

Triss [41]

Answer:

6a^3+ 22a^4+ 14a-10

Step-by-step explanation:

6a^3 10a^2 12a^2 20a -6a -10

7 0

3 years ago

<img src="https://tex.z-dn.net/?f=%5Cfrac%7B%5Csec%5Cleft%28x%5Cright%29%7D%7B%5Ccos%5Cleft%28x%5Cright%29%7D-%5Cfrac%7B%5Csin%5

DanielleElmas [232]

Answer:

Step-by-step explanation:

First, convert all the secants and cosecants to cosine and sine, respectively. Recall that $csc(x)=1/sin(x)$ and $sec(x)=1/cos(x)$ .

Thus:

$\frac{sec(x)}{cos(x)} -\frac{sin(x)}{csc(x)cos^2(x)}$

$=\frac{\frac{1}{cos(x)} }{cos(x)} -\frac{sin(x)}{\frac{1}{sin(x)}cos^2(x) }$

Let's do the first part first: (Recall how to divide fractions)

$\frac{\frac{1}{cos(x)} }{cos(x)}=\frac{1}{cos(x)} \cdot \frac{1}{cos(x)}=\frac{1}{cos^2(x)}$

For the second term:

$\frac{sin(x)}{\frac{cos^2(x)}{sin(x)} } =\frac{sin(x)}{1} \cdot\frac{sin(x)}{cos^2(x)}=\frac{sin^2(x)}{cos^2(x)}$

So, all together: (same denominator; combine terms)

$\frac{1}{cos^2(x)}-\frac{sin^2(x)}{cos^2(x)}=\frac{1-sin^2(x)}{cos^2(x)}$

Note the numerator; it can be derived from the Pythagorean Identity:

$sin^2(x)+cos^2(x)=1; cos^2(x)=1-sin^2(x)$

Thus, we can substitute the numerator:

$\frac{1-sin^2(x)}{cos^2(x)}=\frac{cos^2(x)}{cos^2(x)}=1$

Everything simplifies to 1.

7 0

2 years ago

A regulation baseball field measures 90 feet between each base. What is the distance around the bases in meters?

Alex787 [66]

assuming that the bases are placed correctly, the bases connected draw a square, each side being 90 ft long. We multiply 90 by the amount of sides(4) to find the total distance/perimeter = 360.

3 0

3 years ago

Please help me solve this problem

sergiy2304 [10]

Answer:

-2/3x+6

Step-by-step explanation:

6 0

3 years ago

Read 2 more answers

If -2x+xy=30 and y=8,then what is the value of x?

Dafna1 [17]

-2x + xy = 30.....when y = 8

-2x + 8x = 30
6x = 30
x = 30/6
x = 5 <==

3 0

3 years ago

Read 2 more answers