Passing is a good goal.
pH = -log H+
7.2 = -log H+
-7.2 = log H+
10^(-7.2) = H+
Answer: H+ = 10^(-7.2), third choice
We will use the following law of indices (or 'index law') to check each pair of expression
![x^{ \frac{m}{n}} = ( \sqrt[n]{x} )^{m}](https://tex.z-dn.net/?f=%20x%5E%7B%20%5Cfrac%7Bm%7D%7Bn%7D%7D%20%3D%20%28%20%5Csqrt%5Bn%5D%7Bx%7D%20%29%5E%7Bm%7D%20)
With fractional power, the denominator is the root and the numerator is the power of the term. When the denominator is 2, we usually only write the normal square symbol (√). Denominator other than 2, we usually write the value of the root, for example, the cubic root ∛
Option A - Incorrect

should equal to
Option B - Correct
does equal to

Option C - Incorrect

should equal to

Option D - Incorrect

should equal to
~ Simplifying
-2(7x + -5) = -14x + 10
~ Reorder the terms:
-2(-5 + 7x) = -14x + 10
(-5 * -2 + 7x * -2) = -14x + 10
(10 + -14x) = -14x + 10
~ Reorder the terms:
10 + -14x = 10 + -14x
~ Add '-10' to each side of the equation.
10 + -10 + -14x = 10 + -10 + -14x
~ Combine like terms: 10 + -10 = 0
0 + -14x = 10 + -10 + -14x
-14x = 10 + -10 + -14x
~ Combine like terms: 10 + -10 = 0
-14x = 0 + -14x
-14x = -14x
~ Add '14x' to each side of the equation.
-14x + 14x = -14x + 14x
~ Combine like terms: -14x + 14x = 0
0 = -14x + 14x
~ Combine like terms: -14x + 14x = 0
0 = 0
~ Solving
0 = 0
~ This equation is an identity, all real numbers are solutions.
Without the screenshot, it's fairly difficult to know what your teacher wants exactly. I found this similar problem
brainly.com/question/13583475
which might help. It sounds like you have 4 semicircles which can be thought of as a division problem 12/3 = 4. Note how I'm dividing by 3 which is the width of each section (eg: from 6 to 9 is 9-6 = 3 units)
I think there is a .5 percent chance i added all numbers and divided by 6[the blue marbles]