<h3>Answer:</h3>
(5, -2, -3)
<h3>Explanation:</h3>
We assume your equations are ...
- x +3y -z = 2
- 4x +2y +5z = 1
- 3x +0y +z = 12
These have solution (x, y, z) = (5, -2, -3).
_____
<em>How we know</em>
Trying the choices in the last equation eliminates the first and last. Trying the second choice in the first equation eliminates it, leaving the 3rd choice as the answer you're looking for.
We also know because we can ask a graphing calculator to solve the matrix equation (or row-reduce the augmented matrix).
<em>Comment on this problem</em>
The hardest part of this problem is figuring your intent. The equations are not well-separated, so we have a hard time telling what is a constant and what is a coefficient. It took a couple of guesses to sort it out. A little editing before posting would be helpful.
You can start by subtracting different equations from each other.
3x + 2y + 3z = 1
subtract
3x + 2y + z = 7
2z = -6
divide by 2
z = -3
add the following two expressions together:
3x + 2y + z = 7
3x + 2y + 3z =1
6x + 4y + 4z = 8
subtract the following two expressions:
6x + 4y + 4z = 8
5x + 5y + 4z = 3
x - y = 5
^multiply the whole equation above by 3
3x - 3y = 15
subtract the following two expressions:
3x - 3y = 15
3x + 2y = 10
-5y = 5
divide each side by -5
y=-1
take the following expression from earlier:
x - y = 5
substitute y value into above equation
x - - 1 = 5
2 negatives make a positive
x + 1 = 5
subtract 1 from each side
x = 4
Therefore x = 4, y = -1, z = -3
I checked these with all 3 equations and they worked :)
(it's quite complicated, comment if you don't understand anything) :)
Answer:
20.903
Step-by-step explanation:
Answer: 18 1/6 feet
Step-by-step explanation:
From the question, we are informed that the rectangular sand box has a length of 5 1/3 feet and a width of 3 3/4 feet.
The perimeter would be calculated as:
= 2(length + width)
= 2( 5 1/3 + 3 3/4)
= 2( 5 4/12 + 3 9/12)
= 2( 8 13/12)
= 2 (9 1/12)
= 2 × 9 1/12
= 2 × 109/12
= 218/12
= 18 2/12
= 18 1/6 feet
