Answer:
The addition rule for probabilities describes two formulas, one for the probability for either of two mutually exclusive events happening and the other for the probability of two non-mutually exclusive events happening.
The first formula is just the sum of the probabilities of the two events. The second formula is the sum of the probabilities of the two events minus the probability that both will occur.
When applying indirect proofs, we assume the negation of the conclusion is true, and show that this assumption would lead to nonsense, or contradiction.
In our case we assume a is not smaller than 7, that is we assume a≥7.
a≥7 then, multiplying both sides by 3:
3a≥21, then, adding both sides 7:
3a+7≥28,
which is a contradiction because 3a+7 is smaller than 28.
So our assumption is wrong, which means the opposite of it is correct.
Answer: assume a≥7
Completing the square is a method used to solve a quadratic equation by changing the shape of the equation so that the left side is a perfect square trinomial.
The following equation makes more sense to solve it complete squares:
x² + 20x = 52
We have then:
x² + 20x + (10) ^ 2 = 52 + 100
(x + 10) ² = 152
Answer:
The most sense to solve by completing the square is for:
B) x² + 20x = 52
Answer:
x = ±i(√6 / 2)
General Formulas and Concepts:
<u>Pre-Algebra</u>
<u>Algebra I</u>
<u>Algebra II</u>
Imaginary root i
Step-by-step explanation:
<u>Step 1: Define</u>
<em>Identify</em>
2x² + 3 = 0
<u>Step 2: Solve for </u><em><u>x</u></em>
- [Subtraction Property of Equality] Subtract 3 on both sides: 2x² = -3
- [Division Property of Equality] Divide 2 on both sides: x² = -3/2
- [Equality Property] Square root both sides: x = ±√(-3/2)
- Simplify: x = ±i(√6 / 2)
