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4 years ago

What expression is equivalent to -21? A. 9-(-12) B. 9+(-12) C. -9+12 D. -9-12

Mathematics

2 answers:

LuckyWell [14K]4 years ago

5 0

Answer:

Step-by-step explanation:

-9 - 12

-(9 + 12)

-(21)

-21

xz_007 [3.2K]4 years ago

4 0

Answer:

Step-by-step explanation:

-9-12 = -21

hope this helped :)

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So i need help with the question below.

Shkiper50 [21]

Answer:

Option (1)

Step-by-step explanation:

Option (1)

$3\frac{3}{9}+7\frac{6}{11}=10\frac{87}{99}$

$3\frac{3}{9}+7\frac{6}{11}$ $=3+\frac{3}{9}+7+\frac{6}{11}$

$=(3+7)+(\frac{3}{9}+\frac{6}{11})$

$=10+(\frac{3}{9}\times \frac{11}{11})+(\frac{6}{11}\times \frac{9}{9})$

$=10+(\frac{33}{99}+\frac{54}{99})$

$=10+\frac{87}{99}$

$=10\frac{87}{99}$

True.

Option (2)

$2\frac{3}{8}+6\frac{4}{5}=8\frac{12}{40}$

$2\frac{3}{8}+6\frac{4}{5}=2+\frac{3}{8}+6+\frac{4}{5}$

$=(2+6)+(\frac{3}{8}+\frac{4}{5})$

$=(8)+(\frac{3}{8}\times \frac{5}{5} +\frac{4}{5}\times \frac{8}{8})$

$=8+(\frac{15}{40}+\frac{32}{40})$

$=8+\frac{47}{40}$

$=8+\frac{40}{40}+\frac{7}{40}$

$=8+1+\frac{7}{40}$

$=9+\frac{7}{40}$

$=9\frac{7}{40}$

False.

Option(3)

$3\frac{3}{7}+4\frac{2}{3}=7\frac{2}{21}$

$3\frac{3}{7}+4\frac{2}{3}=(3+\frac{3}{7})+(4+\frac{2}{3})$

$=(3+4)+(\frac{3}{7}+\frac{2}{3})$

$=7+(\frac{3}{7}\times \frac{3}{3} +\frac{2}{3}\times \frac{7}{7})$

$=7+(\frac{9}{21}+\frac{14}{21})$

$=7+(\frac{23}{21})$

$=7+(\frac{21}{21}+\frac{2}{21})$

$=8+\frac{1}{21}$

$=8\frac{1}{21}$

False.

Option (4)

$4\frac{5}{6}+5\frac{5}{7}=9\frac{10}{13}$

$4\frac{5}{6}+5\frac{5}{7}=4+\frac{5}{6}+5+\frac{5}{7}$

$=(4+5)+(\frac{5}{6}+\frac{5}{7})$

$=9+(\frac{5}{6}\times \frac{7}{7}+\frac{5}{7}\times \frac{6}{6})$

$=9+(\frac{35}{42}+\frac{30}{42})$

$=9+\frac{65}{42}$

$=9+(\frac{42}{42}+\frac{23}{42})$

$=9+1+\frac{23}{42}$

$=10\frac{23}{42}$

False.

Therefore, Option (1) is the answer.

8 0

3 years ago

Please:<br> Divide 24 in ratio 3:5

nalin [4]

24/8 = 3

3x3 = 9
5x3=15

so
<span> 24 in ratio 3:5 = 9:15</span>

3 0

3 years ago

10 POINTS ARE AWARDED! :(

amid [387]

Answer:

Step-by-step explanation:

An index number is a number which is raised to a power. The power, also known as the index, tells you how many times you have to multiply the number by itself. For example, 2^5 means that you have to multiply 2 by itself five times = 2×2×2×2×2 = 32. There are a number of important rules of index numbers: y^a × y^b = y.

3 0

3 years ago

Please only answer if you're confident.

lina2011 [118]

Answer: ∠B=70°

Step-by-step explanation:

It is shown in the diagram that ∠A and ∠B is vertical angles.

Vertical angle theorem: opposite angles are congruent.

<u>Solve:</u>

∠A=∠B

8x+6=4x+38

4x=32

x=8

4 0

3 years ago

Read 2 more answers

Are the triangles similar? If so, state the similarity and the postulate or theorem that justifies your answer.

kow [346]

Answer: The triangles are not similar.

Step-by-step explanation:

Two figures are similar simply if they have the same shape, but not necessarily the same size. In a more mathematical sense, similar figures have the same angle measures and proportionate side lengths.

<em>For reference, side lengths are proportionate when the ratios between corresponding/matching sides are the same.</em>

Since we do not have any angles, we will try using the SSS Similarity Theorem, which states that if all three sides of both triangles are in proportion, then the triangles are similar. We will first list all the side lengths and match corresponding ones.

$\triangle ABC \rightarrow 18,20,32\\ \triangle UVT \rightarrow 14,15,24$

Since we matched corresponding sides, we can now check whether they have the same ratio).

$\frac{18}{14}=\frac{20}{15}=\frac{32}{24}$

$\frac{9}{7}=\frac{4}{3}=\frac{4}{3}$

Not all of the side lengths have the same ratio, so these triangles aren't similar. you must multiply 14 by 9/7 to get to 18, but you need to multiply the other two sides by 4/3 to get to their

4 0

2 years ago