How does the periodic table help to predict the properties of elements?
A. Elements in the same group have similar properties
B. Elements in the same period have similar properties
C. The number of protons in an atom's nucleus
D. Elements with higher atomic numbers are more reactive
Elements with lower atomic masses are more reactive
A. Elements in the same group have similar properties
How many hydrogens does ethanol have?
A. One
B. Two
C. Six
A. One
If the atomic number of an element is six and the atomic mass is 15, how many neutrons does it have?
A. 6 Neutrons
B. 9 Neutrons
C. 15 Neutrons
B. 9 Neutrons
-5x=-30
x=_
To solve for x, we can divide both sides of the equation by -5:
-5x = -30
x = -30 / -5
x = 6
So, x = 6.
12-x/9=11
x=_
To solve for x, we need to isolate it on one side of the equation.
We start by multiplying both sides of the equation by 9 to eliminate the denominator:
9*(12 - x)/9 = 11 * 9
12 - x = 99
Next, we subtract 12 from both sides of the equation:
12 - x - 12 = 99 - 12
-x = 87
Finally, we multiply both sides by -1 to solve for x:
(-1) * (-x) = (-1) * 87
x = -87
So, x is equal to -87.
-20=-5+3x
To solve for x, we want to isolate it on one side of the equation.
Starting with the equation -20 = -5 + 3x, we can begin by subtracting -5 from both sides:
-20 + 5 = 3x
-15 = 3x
Next, we can divide both sides of the equation by 3 to solve for x:
-15/3 = 3x/3
-5 = x
So, x is equal to -5.
20=5-3/8x
To solve for x, we want to isolate it on one side of the equation.
Starting with the equation 20 = 5 - (3/8)x, we can begin by subtracting 5 from both sides:
20 - 5 = - (3/8)x
15 = - (3/8)x
Next, we can multiply both sides of the equation by -8/3 to solve for x:
(15) * (-8/3) = - (3/8)x * (-8/3)
-40 = x
So, x is equal to -40.
7(4x-15)=63
To solve for x, we want to simplify the equation and isolate x on one side.
Starting with the equation 7(4x-15) = 63, we can begin by distributing 7 to both terms within the parentheses:
28x - 105 = 63
Next, we can add 105 to both sides of the equation:
28x - 105 + 105 = 63 + 105
28x = 168
Finally, we can solve for x by dividing both sides of the equation by 28:
(28x) / 28 = 168 / 28
x = 6
So, x is equal to 6.
-2(3x-15)-25=35
To solve for x, we want to simplify the equation and isolate x on one side.
Starting with the equation -2(3x-15) - 25 = 35, we can begin by distributing -2 to both terms within the parentheses:
-6x + 30 - 25 = 35
Next, we can combine like terms:
-6x + 5 = 35
Next, we subtract 5 from both sides of the equation:
-6x + 5 - 5 = 35 - 5
-6x = 30
Finally, we can solve for x by dividing both sides of the equation by -6:
(-6x) / -6 = 30 / -6
x = -5
So, x is equal to -5.
12x+5=10x-11
To solve for x, we want to simplify the equation and isolate x on one side.
Starting with the equation 12x + 5 = 10x - 11, we can begin by subtracting 10x from both sides:
12x + 5 - 10x = 10x - 11 - 10x
2x + 5 = -11
Next, we subtract 5 from both sides of the equation:
2x + 5 - 5 = -11 - 5
2x = -16
Finally, we can solve for x by dividing both sides of the equation by 2:
(2x) / 2 = -16 / 2
x = -8
So, x is equal to -8.
At the beginning of the month, a song on a streaming service already had 1,000 listens, and was getting 38 new listens each day. Meanwhile, a different song already had 900 listens, and was getting 40 new listens each day. Write an equation to show the number of days it would take for the two songs to have the same number of listens. Use x as your variable.
Let's call the number of days it will take for the two songs to have the same number of listens x.
For the first song, the number of listens after x days can be represented as: 1000 + 38x.
For the second song, the number of listens after x days can be represented as: 900 + 40x.
To find the number of days it will take for the two songs to have the same number of listens, we can set these two expressions equal to each other:
1000 + 38x = 900 + 40x
Now, we can solve this equation for x by subtracting 38x from both sides and subtracting 900 from both sides:
1000 - 900 = 40x - 38x
100 = 2x
Finally, divide both sides by 2:
100/2 = 2x/2
50 = x
Therefore, it will take 50 days for the two songs to have the same number of listens.
An ice skating rink has two ways you can use the facility. The first option is to pay $10 per visit.
The second option is to pay $32 per month, and $6 per visit. Write and solve an equation to show the number of visits it would take for the cost of the two plans to be equal. (1 point)
A. 10 = 32 + 6x : x = -3
B. 10х = 32 + 6x : x = 4
C. 10х = 32 + 6x ; x = 8
D. 10х = 32 - 6x ; x = 2
To find the number of visits it would take for the cost of the two plans to be equal, we need to set up an equation.
Let's represent the number of visits as x.
For the first option, the cost is a flat rate of $10 per visit.
For the second option, the cost is $32 per month (regardless of the number of visits) plus an additional $6 per visit.
So, the equation would be:
10x = 32 + 6x
To solve for x, we can subtract 6x from both sides:
10x - 6x = 32 + 6x - 6x
This simplifies to:
4x = 32
Finally, we divide both sides by 4 to solve for x:
x = 32/4
x = 8
Therefore, the correct answer is C. 10x = 32 + 6x ; x = 8, which means it would take 8 visits for the cost of the two plans to be equal.
At the beginning of the month, a song on a streaming service had 700 listens, and it was getting 52 new listens each day. Meanwhile, a different song had 600 listens, and it was getting 56 new listens each day. When will the two songs have the same number of listens? (1 point)
The songs will have the same number of listens after __ days.
Let's set up an equation to find the number of days it will take for the two songs to have the same number of listens.
For the first song, the number of listens after x days can be represented as: 700 + 52x.
For the second song, the number of listens after x days can be represented as: 600 + 56x.
We want to find the number of days when the two expressions are equal, so we can set them equal to each other:
700 + 52x = 600 + 56x.
Next, we can subtract 52x from both sides:
700 = 600 + 4x.
Then, we can subtract 600 from both sides:
100 = 4x.
Finally, we divide both sides by 4:
100/4 = 4x/4.
25 = x.
Therefore, the two songs will have the same number of listens after 25 days.
Miguel's car has a 20-gallon capacity, and Christina's car has a 16-gallon capacity. Miguel uses 1.5 gallons of gas per week, and Christina uses 1 gallon of gas per week. When will Miguel and Christina have the same amount of gas in their tanks? (1 point)
A. After 1.6 weeks they will have the same amount of gas in their tanks.
B. After 1 week they will have the same amount of gas in their tanks.
C. After 8 weeks they will have the same amount of gas in their tanks
D. After - 8 weeks they will have the same amount of gas in their tanks.
To figure out when Miguel and Christina will have the same amount of gas in their tanks, we need to set up an equation.
Let's represent the number of weeks as x.
For Miguel, the amount of gas used after x weeks can be represented as 1.5x gallons.
For Christina, the amount of gas used after x weeks can be represented as 1x (or simply x) gallons.
Since the amount of gas in their tanks should be the same, we can set the two expressions equal to each other:
1.5x = x
Next, we can subtract x from both sides to isolate the x variable:
1.5x - x = x - x
0.5x = 0
Now, we divide both sides by 0.5 to solve for x:
0.5x/0.5 = 0/0.5
x = 0
Therefore, the correct answer is A. After 1.6 weeks they will have the same amount of gas in their tanks.
Which of the following equations has exactly one solution? (1 point,
A. 3х - 8 = 3x + 8
B. -3х +8 = -3x - 8
C. -8x + 3 = -8x + 3
D. -32-8 = 3x - 8