Step-by-step explanation:
1) -9 = 9 true/false
the answer is false because negative and positive quite unlike in terms.
2) -(-21) = -21
Using the symbols multiplication rule,
Where,
<h2>
+ × + = +</h2><h2>
- × - = +</h2><h2>
- × + = -</h2><h2>
+ × - = -</h2>
Therefore, -(-21) = +21 = 21
⟼ 21 = -21 
Answer:
$907.38
Step-by-step explanation:
We have been given that Mr. Smith's $85,000 condominium is assessed at 35% of value.
First of all, we will find 35% of $85,000 as shown below:



We are also told that the tax rate is $2.70 per $100 of value. Now we will divide $29,750 by 100 as:

Since the tax rate is increased by $0.35 per $100 of value, so the new tax rate will be $2.70 plus $0.35.




Therefore, Mr. Smith's new tax will be $907.38.
The surface area (SA) of a rectangular prism (box) is obtained by the equation,
SA = 2 (LW + WH + LH)
where L is length, W is width, and H is height.
Substituting the values for the dimensions,
SA = 2 (15cm x 22cm + 22cm x 9cm + 15cm x 9 cm) = 1326 cm²
Thus, the surface area of the box is 1326 cm².
The value of <em>x</em> where by exterior angles theorem, ∠DCO equals 2·x, 69° equals the sum of ∠DCO and x° is <em>x </em>= 23°
<h3>What is the exterior angles theorem?</h3>
The exterior angles theorem states that the exterior angle of a triangle is equal to the sum of the opposite interior angles.
The given parameters are;
Points on the circle are; ABCD
Straight lines = AOBE and DCE
Segment CO = Segment CE
∠AOD = 69°
∠CEO = x°
∠OCD = ∠ODC base angles of isosceles triangle
69° = ∠x° + ∠ODC exterior angle of a triangle
∠DOC = 180 - 2×∠ODC (Angle sum property of a triangle)
180 - 2×∠ODC + x° + 69° = 180° (Sum of angles on a straight line are supplementary)
x° + 69° - 2×∠ODC = 0
∠ODC = 2·x° (exterior angle of a triangle is equal to the sum of the opposite interior angles)
69° = x° + ∠ODC = x° + 2·x° = 3·x° (substitution property of equality)
69° = 3·x°
x = 69° ÷ 3 = 23°
Learn more about angles in a triangle here:
brainly.com/question/25215131
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