1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
hram777 [196]
3 years ago
9

-(-21) = -21 true or false

Mathematics
2 answers:
Kryger [21]3 years ago
8 0

Answer:

False

Step-by-step explanation:

-(-21) is positive 21 since there are 2 negative signs, and -21 is negative, therefore they are not the same.

Hope this helps!

jarptica [38.1K]3 years ago
6 0

Answer:

False. It is equal to 21.

Step-by-step explanation:

-(21) would equal -21

However,

- (- 21) equals 21

The two negatives "cancel" each other out.

Answer: False. It is equal to 21.

You might be interested in
He vertices of square pqrs are p -4,0 q 4,3 r 7,-5 and s -1,-18.Show that the diagonals of square pqrs are congruent perpendicul
Anit [1.1K]

Answer:

Step-by-step explanation:

The vertices of the square given are P(-4, 0), Q(4, 3), R(7, -5) and, S(-1, -18)

For this diagonal to be right angle the slope of the diagonal must be m1=-1/m2

So let find the slope of diagonal 1

The two points are P and R

P(-4, 0), R(7, -5)

Slope is given as

m1=∆y/∆x

m1=(y2-y1)/(x2-x1)

m1=-5-0/7--4

m1=-5/7+4

m1=-5/11

Slope of the second diagonal

Which is Q and S

Q(4, 3), S(-1, -18)

m2=∆y/∆x

m2=(y2-y1)/(x2-x1)

m2=(-18-3)/(-1-4)

m2=-21/-5

m2=21/5

So, slope of diagonal 1 is not equal to slope two

This shows that the diagonal of the square are not diagonal.

But the diagonal of a square should be perpendicular, this shows that this is not a square, let prove that with distance between two points

Given two points

(x1,y1) and (x2,y2)

Distance between the two points is

D=√(y2-y1)²+(x2-x1)²

For line PQ

P(-4, 0), Q(4, 3)

PQ=√(3-0)²+(4--4)²

PQ=√(3)²+(4+4)²

PQ=√9+8²

PQ=√9+64

PQ=√73

Also let fine RS

R(7, -5) and, S(-1, -18)

RS=√(-18--5)+(-1-7)

RS=√(-18+5)²+(-1-7)²

RS=√(-13)²+(-8)²

RS=√169+64

RS=√233

Since RS is not equal to PQ then this is not a square, a square is suppose to have equal sides

But I suspect one of the vertices is wrong, vertices S it should have been (-1,-8) and not (-1,-18)

So using S(-1,-8)

Let apply this to the slope

Q(4, 3), S(-1, -8)

m2=∆y/∆x

m2=(y2-y1)/(x2-x1)

m2=(-8-3)/(-1-4)

m2=-11/-5

m2=11/5

Now,

Let find the negative reciprocal of m2

Reciprocal of m2 is 5/11

Then negative of it is -5/11

Which is equal to m1

Then, the square diagonal is perpendicular

6 0
3 years ago
What is the volume of a rectangular prism that is 3 cm by 7 cm by by 7 cm?
natali 33 [55]

Answer:

147 cm^{3}

Step-by-step explanation:

7*7*3 = 147

volume of a rectangular prism = length*width*height, in this case, 7*7*3

hope this helps :)

3 0
3 years ago
The endpoints of one side of a regular pentagon or -1, four and two, three what is the perimeter of the Pentagon
forsale [732]

Answer:

Step-by-step explanation:

(-1,4),(2,3)\\ \\ s^2=(-1-2)^2+(4-3)^2\\ \\ s^2=9+1\\ \\ s^2=10\\ \\ s=\sqrt{10}\\ \\ p=5s\\ \\ p=5\sqrt{10}\ exact\\ \\ p\approx 15.8

8 0
2 years ago
If (5^2)p = 5^12, what is the value of p?
mr Goodwill [35]
Divide both sides by 5^2 (which is 25). So p = (5^12)/25. I can't be bothered to plug in into a calculator but be my guest.
3 0
3 years ago
What is x2+5x=0? Please show all work!
Alexxandr [17]
X2+5x=0
7x+0
divide both sides by 7
7 divided by 0 is 0
x=0
0=0
7 0
3 years ago
Read 2 more answers
Other questions:
  • the table of values represents a linear function. For this function, what is the value of y when x=4?
    7·1 answer
  • What is the approximate volume of a cylinder with a radius of 8 cm and height of 5 cm?
    7·1 answer
  • If x=3+2root2,find the value of xsquare+1/xsquare​
    5·1 answer
  • Diameter: 10 centimeters; height: 14 centimeters
    11·1 answer
  • Image point B'(4, -8) was transformed using the translation (x-2, y + 3). What were the coordinates of B?
    14·1 answer
  • The formula T= 2pi sqrt(L/32) relates the time, T, in seconds for a pendulum with the length, L, in feet, to make one full swing
    12·2 answers
  • The difference of 5 times a number and 8 is 27. which equation below can be used to find the unknown number?
    12·2 answers
  • The school is 4000 meters from Jim house how many kilometers is this
    6·1 answer
  • Benecio worked 40 hours at his two jobs last week. He earned $20 per
    8·1 answer
  • Can anyone help me with this? Please and thank you!
    14·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!