Answer:
x = 1, -7.5
Explanation:
2x² + 13x = 15
Divide the left side of the equation by 2
2(x² + 6.5x) = 15
Divide 6.5 by 2 and square the quotient
6.5/2 = 3.25
3.25² = 10.5625
Add 10.5625 to the left side
2(x² + 6.5x + 10.5625) = 15
Since you have a 2 outside the parentheses, you will be adding 10.5625•2 to the right side.
10.5625 • 2 = 21.125
2(x² + 6.5x + 10.5625) = 36.125
To factor (x² + 6.5x + 10.5625), add b/2 to x
b/2 = 6.5/2 = 3.25
2(x + 3.25)² = 36.125
Divide by 2
(x + 3.25)² = 18.0625
Square root.
(x + 3.25) = √18.0625
x + 3.25 = ±4.25
Subtract 3.25.
x = 4.25 - 3.25 = 1
x = -4.25 - 3.25 = -7.5
x = 1, -7.5
The answer is A, between 0 and 7.
In a pH scale from 0 to 14, we can groups these numbers into acidic, neutral, and alkaline. 7 is the neutral pH value, therefore, 0-7 is always acidic, and 7-14 is alkaline.
The smaller the number is, the more acidic the solution will be. This applies same in alkalis, the larger the pH value is, the more alkaline the solution is.
We can measure the pH of solution with many methods, the easiest way include using a pH paper, more advanced and accurate methods includes using a pH meter.
Answer:
<em>Green</em><em> </em><em>vitriol</em><em>-</em><em> </em><em>FeSO4·7H2O</em>
<em>white</em><em> </em><em>vitriol</em><em>-</em><em> </em><em>ZnSO₄</em>
A reaction is when two or more pure substances combine with each other to form another identity of pure substances. In general from, it is written as:
A + B → C + D
The substances A and B are the reactants, while the substances C and D are the products. Therefore, in a reaction, the products are found at the end or right side of the reaction.
Answer:
200 liters of fluoridated drinking water would have to be consumed by as person to reach the toxic level.
Explanation:
Toxic level of fluoride ions = 0.2 g per 70 kg body weight
Concentration of fluoride ions in drinking water = 1 mg/ L = 0.001 g/L
1 mg = 0.001 g
Let the volume of drinking water consumed by person to reach the toxic level of fluoride concentration be V.
For 70 kg body weight 0.2 grams of fluoride ions will be toxic.
200 liters of fluoridated drinking water would have to be consumed by as person to reach the toxic level.
