Step-by-step explanation:
πrxrxh
3.14 x 3.5 x 3.5 x 10 = 384.65
3.14 x 2 x 2 x 6 = 75.36
Answer: A
Step-by-step explanation:
Take 2 equations that make one of their letters disappear, and add them up:
2x + y + z = 1
x - y + 4z = 0
------------------------
3x + 5z = 1
Do the same with another 2 equations in which the letter, in this case y, can be removed. If you can't, take 2 of 3 equations and equal the value of the letter to make it eliminable.
x - y + 4z = 0
x + 2y - 2z = 3
Since we can't eliminate y, we have multiply as necessary to make it eliminable:
2 (x - y + 4z = 0)
= 2x - 2y + 8z = 0
add all up:
2x - 2y + 8z = 0
x + 2y - 2z = 3
-----------------------------
3x + 6z = 3
Now we've gone from a 3-variable equation to a 2-variable equation.
3x + 5z = 1
3x + 6z = 3
We can solve again by elimination; to get rid of z, for example, we cross multiply. the upper equation by 6 and the lower equation by 5. However, we have to make one of them negative in order to make them eliminable.
6 (3x + 5z = 1)
-5 (3x + 6z = 3)
----------------------------
18x + 30z = 6
-15x - 30z = -15
---------------------------
3x = - 9
Solving for x;
x = 
x = - 3
After finding one variable, we can use our 2-variable equations to find the next variable:
3x + 5z = 1
3 (-3) + 5z = 1
- 9 + 5z = 1
5z = 1 + 9
5z = 10
z = 
z = 2
Having found these 2 variables, we can put them into one of our main 3-variable equations to find the last one:
2x + y + z = 1
2(-3) + y + 2 = 1
- 6 + y + 2 = 1
y - 4 = 1
y = 1 + 4
y = 5
And you've found all the variables in the equation; to prove if they're correct or not, you can replace them in any of the main equations and the result should be equal to each other:
x + 2y - 2z = 3
-3 + 2(5) - 2(2) = 3
- 3 + 10 - 4 = 3
10 - 7 = 3
3 = 3
The formula to finding a discriminant would be b^2-4ac, the b value of this trinomial being -5, the a value being 2, the c value being 3. Then, you plug the values in the equation and solve: (-5)^2-4(2)(3)
This would simplify to 1, meaning there are two solutions since the discriminant value is positive. If it is 0, there is one solution, if it is negative, then there are no real solutions.
Answer:
2000 + .05x >= 2200
Step-by-step explanation:
2000 is how much she already has
.05 is 5% of sales
x is the unknown amount of sales
2200 is how much she needs
The rate is just 5% increase.
Answer:
x = -1
Step-by-step explanation:
<em><u>Add like terms (3 and 7, 2x and -10x and -x)</u></em>
x + 3 + 7 = 2x - 10x - x
x + 10 = -9x
<em><u>Subtract x from both sides:</u></em>
10 = -10x
<em><u>Divide both sides by -10:</u></em>
-1 = x