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
WITCHER [35]
3 years ago
13

The difference of two numbers, a and b, is 21. The difference of 5 times a and two times b is 18. What are the values of a and b

? A. 4,1 B. -19,40 B. 20,1 C. 30,9 D. -8,-29
Mathematics
1 answer:
PSYCHO15rus [73]3 years ago
6 0
A-b=21
5a-2b=18

We can use substitution here. Take the first equation and solve for A. (Picking this one because it's easy)

a = 21+b

Plugin to the second equation:5(21+b)-2b=18
Simplify: 105 + 5b - 2b = 18
Simplify: 105 + 3b = 18
Subtract both sides: 3b = 18-105
Simplify: 3b = -87
Divide: b = -29

Plug back into the first: a=21+b
a = 21 - 29
a = -8

Option D

You might be interested in
You are studying the relationship between the history of early childhood trauma (categorized as trauma/no trauma) and weight in
jeka57 [31]

Answer:

You can decide to <u>reject</u> the Null Hypothesis at p < 0.05.

Step-by-step explanation:

In this case, the relationship between the history of early childhood trauma and weight in adulthood are being studied.

The categories of childhood trauma are:

Trauma and No trauma.

So, number of rows is, <em>r</em> = 2.

The categories of weight in adulthood are:

Low to normal, Overweight, and Obese

So, number of columns is, <em>c</em> = 3.

The distribution of the statistic \chi^{2} is chi-square with (<em>r </em>- 1)(<em>c </em>- 1) degrees of freedom, where <em>r</em> represents the number of rows in the two-way table and <em>c</em> represents the number of columns.

Compute the degrees of freedom as follows:

df = (r-1)(c-1)=(2-1) \times (3-1) = 2

It is provided that the calculated value of Chi-square test statistic is 18.26.

Compute the <em>p</em>-value of the test as follows:

p-value=P(\chi^{2}_{2}\geq 18.26)\\=0.000108\\\approx0.00011

Decision rule:

The null hypothesis will be rejected if the <em>p</em>-value of the test is less than the significance level.

The significance level is, <em>α</em> = 0.05.

<em>p</em>-value = 0.00011 < <em>α</em> = 0.05.

The null hypothesis will be rejected at 5% level of significance.

Thus, the complete statement is:

"You can decide to <u>reject</u> the Null Hypothesis at p < 0.05."

4 0
3 years ago
The bearing of Q from P is 150
Lynna [10]

Answer:

(i) see first attached diagram

(ii) QR = 22.67 km (2 dp)

(iii) 243°

Step-by-step explanation:

A bearing is the angle in degrees measured clockwise from north.

<u />

<u>Part (i)</u>

see first attached diagram

<u>Part (ii)</u>

The angles marked in blue on the second attached diagram are Consecutive Interior Angles.  In this case they add to 180° as the North lines are parallel.

The sum of angles around a point is 360°

⇒ m∠QPR (shown in red on the second attached diagram) = 360 - 150 - (180 - 15) = 45°        

To calculate the distance between Q and R (marked in red on the attached diagram), use the cosine rule.

⇒ QR² = PR² + QP² - 2(PR)(QP)cos(QPR)

⇒ QR² = 32² + 24² - 2(32)(24)cos(45)

⇒ QR² = 513.8839841...

⇒ QR = √513.8839841...

⇒ QR = 22.67 km (2 dp)

<u>Part (iii)</u>

We need to find the angle marked in green on the third attached diagram.

To do this, we need to find the angle marked in pink and the angle marked in orange, then subtract them from 360°

Pink angle = 180 - 150 = 30° (using the same consecutive angle theorem as before)

Orange angle (o) using the sine rule:

⇒ sin(o)/32 = sin(45)/QR

⇒ sin(o) = 32sin(45)/22.67

⇒ sin(o) = 0.9981652337...

⇒ o = 86.52868176...°

Therefore, the green angle = 360 - 30 - 86.52868176... = 243° (nearest degree)

8 0
2 years ago
110,411 in expanded form
Neporo4naja [7]
One hundred and ten thousand , four hundred and eleven

11000 + 400 +11
5 0
3 years ago
Read 2 more answers
I need help please???
melamori03 [73]

Answer:

x < 8

Step-by-step explanation:

Given

x + 4 < 12

Isolate x on the left side by subtracting 4 from both sides

x < 8 ← is the solution

6 0
3 years ago
Read 2 more answers
Which set shows an average of 3?<br> A) A<br> B) B<br> C) A and B<br> D) none of the above
77julia77 [94]

Answer:

B

Step-by-step explanation:

bbbbbb brainless me

5 0
2 years ago
Other questions:
  • Given A = {18, 6, -3, -12} Determine all elements of set A that are in the solution of the inequality 2/3x + 3 &lt; -2x -7
    13·1 answer
  • I need help simplifying -11+5b+6-2b
    5·2 answers
  • To find 19+11+37 lennie added 19 and 11 then be added 37 to the sum .what property did he use ?
    5·1 answer
  • Give the coordinates of a point on the line whose equation in point-slope form is.
    12·1 answer
  • Solve the formula for the indicated variable. W equals XYZ for Z
    8·1 answer
  • 30g of sugar is needed to make 4 cakes. How much sugar is needed for 7 cakes?
    7·2 answers
  • Find the value of x2 for these values of x<br> a: 2 b: 3 c:9 d:10<br> Help Please?
    10·1 answer
  • WILL GIVE BRAINLIEST
    5·1 answer
  • What is the equation of the line perpendicular to y=1/2x+6 that passes through points 4,1
    11·1 answer
  • A function is a type of ___________.
    11·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!