Step-by-step explanation:
In isoceles triangle two sides are equal and two angles are equal.
Then,
∠R = ∠T = (5x-40)°
Then,
∠RTS + ∠STU = 180° (bcoz it lies on a straight line)
(5x-40) ° + 5x = 180°
10x = 220°
x = 22°
Therefore,
Option A is correct✔
To put it in the simplest words :
Get rid of the parentheses and add like so:

<span>Combine like terms
2n^3+n^3= 3n^3
-8n^2 remains the same since there are no like terms for it
8n also remains the same
-9+7=-2
Put all of the numbers together
3n^3-8n^2+8n-2
Final answer:B - the 2nd one</span>
12 is the answer to this quest
No method can prove that the Triangles are congruent .-.
We are told that the circle’s circumference is 12.56 cm. So, to find it’s diameter, we have to divide 12.56 by 3.1416.
The answer is approximately 3.9979 which is VERY close to 4, so we can say that the diameter of the circle is approximately 4 cm.