Answer:
D. Subtraction property of equality
B. 6.5
Step-by-step explanation:
First blank:
The equation is x + 6.5 = 13.
To solve the equation, you want x alone on the left side, showing "x = some number." Since 6.5 is being added to x, you need to SUBTRACT 6.5. You must do the same operation to both sides of an equation, so you need to SUBTRACT 6.5 from both sides of the equation. What allows you to subtract the same number from both sides of an equation is the
<em>D. Subtraction property of equality </em>
Second blank:
Subtract 6.5 from both sides.
x + 6.5 = 13
x + 6.5 - 6.5 = 13 - 6.5
x = 6.5
<em>Answer: B. 6.5</em>
This is one pathway to prove the identity.
Part 1

Part 2

Part 3

As the steps above show, the goal is to get both sides be the same identical expression. You should only work with one side to transform it into the other. In this case, the left side transforms while the right side stays fixed the entire time. The general rule is that you should convert the more complicated expression into a simpler form.
We use other previously established or proven trig identities to work through the steps. For example, I used the pythagorean identity
in the second to last step. I broke the steps into three parts to hopefully make it more manageable.
Answer:
2(x²-8+15)
X1/2=8+-(64-60) /2= 8+-2 /2=
10/2=5 or
6/2=3
So the answer is C. 2(x-3)(x-5)
Answer:
The age of the spear head to the nearest year is 1845 years
Step-by-step explanation:
We know that
half life time of C-14 is 5730 years
so, h=5730
we can use formula

now, we can plug value

an archaeologist in turkey discovers a spear head that contains 80% of its original amount of C-14
so,

we can plug it

now, we can solve for t




So,
The age of the spear head to the nearest year is 1845 years