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
Answer:
question 1: 3
question 2: the number of Valence electrons in the atom
hope it helps
Answer:
a) 320: two significant figures.
b) 2,366: four significant figures.
c) 73.0: three significant figures.
d. 532.5: four significant figures.
Explanation:
Hello there!
In this case, according to the given information, it turns out possible for us to write each number by knowing we move the decimal places to the right as much as the exponent is, and also, we count every figure, even zeros, because they are to the right of the first nonzero digit:
a) 320: two significant figures because the rightmost zero is not preceded o followed by a decimal place.
b) 2,366: four significant figures.
c) 73.0: three significant figures, because the zero is followed by the decimal place.
d. 532.5: four significant figures.
Regards!
The atomic number is always equal to the number of protons. It will be equal to the number of elections also if the atom has a neutral charge.
If you find my answer helpful, please brainliest me!
Molarity=Moles of solute/Volume of solution in L
So
- 0.56M=moles/2.5L
- moles=0.56(2.5)
- moles of Iodine=1.4mol
Mads of Iodine
- Moles(Molar mass)
- 1.4(126.9)
- 177.66g
