Answer:5.9-6.2x
Step-by-step explanation:
a=1.4-2x
b=-0.2x+1.7
3a+b
=3(1.4-2x)+(-0.2x+1.7)
=4.2-6x-0.2x+1.7
=4.2+1.7-6x-0.2x
=5.9-6.2x
Hey there! Hello!
I believe what this question (more of a statement) is asking is to identify what a letter that represents an unknown number is called. Most of the time, i refer to it as just a variable, or an unknown variable. It can also be referred to as just an unknown value.
Feel free to ask me any additional questions if you have any! :-)
Answer:
The are is 1,200 cm squared
Step-by-step explanation:
10 * 20 = 200
20 * 50 = 1000
1000 + 200 = <em><u>1,200cm squared</u></em>
<em><u></u></em>
<em><u>Hope this helped! Have a nice day! Plz mark as brainliest!!!</u></em>
<em><u>-XxDeathshotxX</u></em>
Answer:
His acceleration is 
meters per seconds²
Step-by-step explanation:
Acceleration is the rate of change of the speed
The formula of acceleration is 
, where
is the final speed
is the initial speed- The unit of the acceleration is meters/second²
∵ Jim goes from 70 meters/minute (beginning speed) to
106 meters/minute (final speed) in 9 seconds
∴ His initial speed = 70 meters/minute
- Change it the meter per second
∵ 1 minute = 60 seconds
∴ 
meters/second
∴ = 
meters/second
∵ His final speed = 106 meters/minute
- Change it the meter per second
∴ 
meters/second
∴ = 
meters/second
∵ The time of the change of his speed is 9 seconds
∴ t = 9
∵ The formula of acceleration is
- Substitute the values of t, and in the formula above
∴ 
∴ His acceleration is meters per seconds²
Answer: 490 grams of the first alloy should be used.
30 grams of the second alloy should be used.
Step-by-step explanation:
Let x represent the weight of the first alloy in grams that should be used.
Let y represent the weight of the second alloy in grams that should be used.
A chemist has two alloys, one of which is 15% gold and 20% lead. This means that the amount of gold and lead in the first alloy is
0.15x and 0.2x
The second alloy contains 30% gold and 50% lead. This means that the amount of gold and lead in the second alloy is
0.3y and 0.5y
If the alloy to be made contains 82.5 g of gold, it means that
0.15x + 0.3y = 82.5 - - - - - - - - - - - -1
The second alloy would also contain 113 g of lead. This means that
0.2x + 0.5y = 113 - - - - - - - - - - - - -2
Multiplying equation 1 by 0.2 and equation 2 by 0.15, it becomes
0.03x + 0.06y = 16.5
0.03x + 0.075y = 16.95
Subtracting, it becomes
- 0.015y = - 0.45
y = - 0.45/- 0.015
y = 30
Substituting y = 30 into equation 1, it becomes
0.15x + 0.3 × 30 = 82.5
0.15x + 9 = 82.5
0.15x = 82.5 - 9 = 73.5
x = 73.5/0.15
x = 490
