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
Lady_Fox [76]
3 years ago
13

Joan is 5 years older than Ellen, and 3 years ago the sum of their ages was 17 years. In how many years will Joan be 21 years ol

d?
Mathematics
1 answer:
slavikrds [6]3 years ago
5 0

Answer:

7

Step-by-step explanation:

If J is Joan's current age and E is Ellen's current age, then:

J = E + 5

(J - 3) + (E - 3) = 17

Solve the first equation for E:

E = J - 5

Substitute into the second:

(J - 3) + (J - 5 - 3) = 17

J - 3 + J - 8 = 17

2J - 11 = 17

2J = 28

J = 14

Joan is 14, so in 7 years, she will be 21.

You might be interested in
How do you do this? I have no idea
Helga [31]

Answer:

c

Step-by-step explanation:

5 0
2 years ago
Which describes the calculations that could be used to solve this problem? Lauren has 42 muffins to pack into boxes and bags. Sh
Marat540 [252]
The correct answer is D, 'Subtract 42 - 12. Then divide the difference by 3'. Lauren has 42 muffins, and she can put 12 of them into a box, leaving her with 30 muffins to fit into bags. If she can fit 3 muffins in each bag, and she wants to know how many bags she needs, then she needs to divide 30 by 3 to get 10. This means that she will need 10 bags of 3 muffins to completely pack 30 muffins. She started with 42, but 12 of those fit into the original box, so we don't have to worry about it.

Hope this helps!
6 0
3 years ago
Read 2 more answers
James has $7.60 in nickels and quarters. He has 4 fewer nickels than quarters. How many of each coin does he have? ​
Rainbow [258]
26 quarters, 22 nickels
4 0
2 years ago
Solve the system of equations: <br> X+y+z=5<br> -3x-4y+4z=15<br> 2x-y-4z=-8
atroni [7]

Answer:

  (x, y, z) = (3, -2, 4)

Step-by-step explanation:

The attachment shows a solution using a graphing calculator where the first equation is solved for z, and that expression is substituted into each of the other two equations. The solution to that system is (x, y) = (3, -2). Using these values in the expression for z, we find ...

  z = 5 -(3 +(-2)) = 4

The solution is (x, y, z) = (3, -2, 4).

__

Your graphing calculator and/or online tools can give you the reduced row echelon form of the augmented matrix representing the system:

  \left[\begin{array}{ccc|c}1&1&1&5\\-3&-4&4&15\\2&-1&-4&-8\end{array}\right]

__

If you're solving by hand, you can do the substitution described above to eliminate z from one equation. You can eliminate z from another equation by adding the last two:

  -3x -4y +4(5 -x -y) = 15   ⇒   -7x -8y = -5

  (-3x -4y +4z) +(2x -y -4z) = (15) +(-8)   ⇒   -x -5y = 7

This pair of equations can be solved for x and y in any of the usual ways. Using the second equation to substitute for x, for example, gives you ...

  -7(-5y -7) -8y = -5   ⇒   27y = -54   ⇒   y = -2

  x = -5(-2) -7 = 3

  z = 5 -(3) -(-2) = 4

_____

<em>Additional comment</em>

If all that is needed is a solution, we prefer a graphical or matrix approach. These take about the same amount of time. Both require a little additional effort to determine exact values when the solutions are not integers.

6 0
2 years ago
Graph the linear equation using intercepts. Use a graphing calculator to check your graph.
Gekata [30.6K]

Answer:

desmos .com

Step-by-step explanation:

4 0
2 years ago
Other questions:
  • The quotient of a number 2 is 7
    14·1 answer
  • how much does britney need to buy 2 pearl bracelets and 2 emerald rings emerald ring price 6,395.00 Pearl bracelets prince 5,314
    6·2 answers
  • For the quadratic equation, state the axis of symmetry, vertex, and any intercepts.
    7·1 answer
  • Given f (x) = 4x + 3 and g (x) = 2x - 1
    7·1 answer
  • Please help me please help me please help me
    7·1 answer
  • An investment gains $5 in value on one day. The next day, it loses $3 in value. Represent each of these using integers.
    6·1 answer
  • The distance between points A and B is?
    10·1 answer
  • The height, h, in feet of a piece of cloth tied to a waterwheel in relation to sea level as a function of time, t, in seconds ca
    11·1 answer
  • If I make 2,500 dollars a minute.How much money will I make in 8 hours?
    13·2 answers
  • Tuesday
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!