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
Aleks04 [339]
3 years ago
8

The sum of two numbers is 21,and their difference is 9

Mathematics
2 answers:
Nimfa-mama [501]3 years ago
8 0

Answer:

The numbers are 15 and 6.

Step-by-step explanation:

We can solve the problem algebraically (using equations). First, write equations that represent the situation.

Choose variables to represent the numbers:

let the numbers be "x" and "y"

Take apart each section of the problem and make an equation.

"The sum of two numbers is 21"

x + y = 21             Sum means the answer when you add numbers

"Their difference is 9"

x - y = 9               Difference means the answer when you subtract numbers

Using the two equations, you can solve using <u>elimination</u>. With this method, you get rid of one of the variables, so you can easily solve for the other one. You can use elimination when one of your variables have the same variable number. Both equations have "1x" and "1y" ("1" is never written).

Add the equations together by adding normally, with each of the terms with the same variable.

.     x + y = 21             Add each term

<u>+     x - y = 9</u>            (x + x = 2x)     (y + (-y) = 0)     (21 + 9 = 30)

.   2x + 0 = 30         "y" variable cancelled out

.          2x = 30        

.       2x/2 = 30/2         Divide both sides by "2" to isolate "x"

.            x = 15         Answer for one number

To find the other number, substitute 'x' for 15 into one of the equations.

x + y = 21

15 + y = 21         Isolate "y" now

15 - 15 + y = 21 - 15         Subtract 15 from both sides

y = 21 - 15         15-15 cancelled out on the left side. Solve right side.

y = 6       Answer for second number

Therefore the two numbers are 15 and 6.

Ghella [55]3 years ago
3 0
let's say the two numbers are x and x + 9. so we know x + x + 9 = 21, so 2x + 9 = 21. subtract 9 from both dies to get 12 = 2x. divide both sides by 2 to get x = 6. so your two numbers are 6 and 15.
You might be interested in
WHAT IS THE SQUARE ROOT OF POTATO?
SIZIF [17.4K]

Answer:

Do you mean square root of pi?

Step-by-step explanation:

Because if it is then the answer is 1.772453850905516

8 0
3 years ago
Help me with this question please!! no links!!
In-s [12.5K]
50.24
4 squared is 16
16•3.14= 50.24
A= 3.14(4)^2
:)
3 0
3 years ago
2/3 divided by 1/3 reduced to lowest term
Margaret [11]
\bf \cfrac{2}{3}\div \cfrac{1}{3}\implies \cfrac{2}{3}\times  \cfrac{3}{1}\implies \cfrac{2\times 3}{3\times 1}

simplify away
6 0
3 years ago
Read 2 more answers
Find the slope of the line of best fit shown below.
grandymaker [24]
The Answer is A, 1/2
7 0
3 years ago
What is measure of angle D?<br>pls provide explanation​
liubo4ka [24]
130 (hsjdjcjcjdjjxxjxjjxjzjsjsjsjak)
8 0
3 years ago
Other questions:
  • A department store sold 51 51 shirts one day. All short-sleeved shirts cost $14.00 $ 14.00 each and all long-sleeved shirts cost
    8·1 answer
  • The complement of an angle is one-sixth the measure of the supplement of the angle. What is the measure of the complement angle?
    13·2 answers
  • Reflect the figure over the line <br> x<br> =<br> 2<br> x=2.
    11·1 answer
  • Can someone please help?
    13·2 answers
  • ANSWER ASAP!!! PLEASE... I really need an answer ;-; ..
    7·2 answers
  • Evaluate the expression for the given value(s) of the variables s=7 k=4 x=6 8 - k+ x
    8·1 answer
  • Evaluate (x + y)for x= -3 and y= 5.<br> A.-1/2<br> B.0<br> C.1<br> D.2
    11·2 answers
  • Please help me get the right answer urgently. And I’ll give you Brainliest in seconds.
    6·1 answer
  • BRAINLIEST PLEASE HELP AND YOU GET BRAINLIEST BRAINLIEST GET BRAINLIEST HELP ME FOR BRAINLIEST​
    8·2 answers
  • Given Trapezoid JOKE with m
    7·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!