Answer:
4.5×10^17 m²
Step-by-step explanation:
The radius is half the diameter, so we can make the substitution r=d/2 into the formula to get ...
A = 4πr² = 4π(d/2)² = πd²
Filling in the given values and doing the arithmetic gives ...
A = 3.14×(3.8×10^8 m)² = 45.3416×10^16 m²
A ≈ 4.5×10^17 m²
__
We round to 2 significant digits because that is the precision of the given diameter.
Answer:
Step-by-step explanation:
It seems this system of equations would be solved easier using the elimination method (the x and y values are lined up).
Multiply everything in the first equation by -2 (we want the 4x to be able to cancel out with a -4x).
Now line up the equations (they are already lined up - convenient) and add them from top to bottom.
The -4x and 4x are opposites, so they cancel out.
Adding 6y and 2y gives you 8y, and adding -12 and 4 gives you -8.
Divide both sides by 8.
Since you have the y-value you can substitute this in to the second (or first equation, it doesn't necessarily matter) equation.
Simplify.
Add 2 to both sides.
Divide both sides by 4.
The final answer is 
.
This will be easier to write, and a lot easier to read, if we temporarily
use another symbol ... say, 'Q' ... to represent ' sin(2x) ' .
Here we go:
Original equation: Q² - 0.5 Q = 0
Factor the left side: Q (Q - 0.5) = 0
This equation is true if either factor is zero:
-- If Q=0, then sin(2x) = 0
2x = 0°, 180°, 360°
x = 0°, 90°, 180°
-- If (Q-0.5) = 0, then Q = 0.5
sin(2x) = 0.5
2x = 30°, 150°
x = 15°, 75°
The whole collection of solutions
between 0° and 360° :
x = 0°, 15°, 75°, 90°, 180° .
Answer:
Step-by-step explanation:
-8 (x - 3y - 9) = distribute the -8 through the parenthesis
-8(x) - 8(-3y) - 8(-9) =
-8x + 24y + 72
this is the distributive property....u are distributing the -8 through the parenthesis...what that means is ur multiplying -8 by everything in the parenthesis....you do this to remove the parenthesis
