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
NISA [10]
3 years ago
7

What is the value of the expression below? 13 - (-9)

Mathematics
1 answer:
yuradex [85]3 years ago
7 0
13 - (-9)
13 - 9 = 4
You might be interested in
How many different digits are needed for the base 6 system?​
lorasvet [3.4K]

Answer:

0, 1, 2, 3, 4 and 5

Step-by-step explanation:

In a nutshell, base six  is a number system that employs the numbers 0 through 5 instead of 0 through 9 in each digit. As a result, a number that would be stated as 6 in base ten is written as 10. We count one, two, three, four, five, ten, eleven, twelve, thirteen, fourteen, fifteen, twenty, and so on.

6 0
3 years ago
Given triangle DEF where ∠D = (7b +1)∘, ∠E = (2b + 1)∘, and ∠F = ( b + 8)∘. What is the measure of ∠E?
____ [38]
<h3>Answer:  35 (choice C)</h3>

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

Explanation:

For any triangle, the three interior angles always add to 180.

D+E+F = 180

(7b+1) + (2b+1) + (b+8) = 180

(7b+2b+b) + (1+1+8) = 180

10b+10 = 180

10b = 180-10

10b = 170

b = 170/10

b = 17

Use this value of b to find the three angle measures

  • D = 7b+1 = 7*17+1 = 119+1 = 120
  • E = 2b+1 = 2*17+1 = 34+1 = 35 degrees
  • F = b+8 = 17+8 = 25

As a check,

D+E+F = 120+35+25 = 120+60 = 180

which helps confirm the correct answers.

3 0
3 years ago
Can someone answer these questions ? thank you
Naya [18.7K]

Answer:

Step-by-step explanation:

12a)To rationalize the denominator, multiply the denominator and numerator by √5.

\frac{15}{\sqrt{5}}=\frac{15*\sqrt{5}}{\sqrt{5}*\sqrt{5}}\\\\=\frac{15\sqrt{5}}{5}\\\\=3\sqrt{5}

b) (a+b)² = a² + 2ab + b²

(1 +√3)² = 1² + 2*1*√3 + (√3)²

= 1 + 2√3 + 3

= 4 + 2√3

a = 4 ; b =2

13) (a + b)(a - b) = a² - b²

\frac{(6-\sqrt{5})(6+\sqrt{5})}{\sqrt{31}}=\frac{6^{2}-(\sqrt{5})^{2}}{\sqrt{31}}\\\\ =\frac{36-5}{\sqrt{31}}\\\\=\frac{31}{\sqrt{31}}\\\\=\frac{31*\sqrt{31}}{\sqrt{31}*\sqrt{31}}\\\\=\frac{31\sqrt{31}}{31}\\\\=\sqrt{31}

5 0
3 years ago
How do you solve this???????<br> 3x+6=-5-2x-6
Elina [12.6K]

Answer:

Step-by-step explanation:

3x+6=-5-2x-6

+2x.        +2x

5x+6= -5-6

5x+6= -11

    -6.  -6

5x= -17

divide by 5

x= -3.4      

4 0
3 years ago
Jia is skipping a rock across a pond. The sequence {4.2, 3.57, 3.0345, 2.5793, …} describes the height of the rock on each succe
mylen [45]

Answer:

u_n=4.2(0.85)^{n-1}

Step-by-step explanation:

u_1=4.2\\u_2=3.57\\u_3=3.0345\\u_4=2.5793

Geometric formula sequence:   u_n=ar^{(n-1)}

(where a is the first term of the sequence and r is the common ratio)

To find the common ratio, divide one of the terms by the previous term:

r=\frac{u_2}{u_1} =\frac{3.57}{4.2} =0.85

From inspection, a=4.2

Therefore, u_n=4.2(0.85)^{n-1}

8 0
2 years ago
Read 2 more answers
Other questions:
  • Jack just opened a checking account at the bank. Within the first month, he deposited three checks for $34.98, $51.02, and $51.2
    10·1 answer
  • Explain why the solution to the absolute value inequality |4x-9|&gt;-12 is all real numbers
    11·1 answer
  • a van is carrying 486 pounds there are 27 boxes in the van what is the average weight of each box in the van
    8·2 answers
  • Using linked lists or a resizing array; develop a weighted quick-union implementation that removes the restriction on needing th
    9·1 answer
  • A fraction is less than 1. Choose a counterexample that will prove this conjecture false​
    14·1 answer
  • Point R is located at  (3,2) and point S is located at (8,15) . What are the coordinates of the point that partitions the direct
    7·1 answer
  • Which of the following ordered pairs represents the solution to the system given below?
    8·1 answer
  • How many feet of shelves will the library have after the new shelves are installed?
    11·1 answer
  • There are 3 paper clips and 5 erasers in a paper stack. If 2 items are drawn at random without replacement what is the probabili
    13·1 answer
  • Flying against the wind, an airplane travels 2520 kilometers in 4 hours. Flying with the wind, the same plane travels 9450 kilom
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!