<span>{4x−3y=15
{2x+2y=4
multiply -2 to both sides to the second equation
-4x - 4y = -8
</span>{4x−3y=15
{-4x - 4y = -8
---------------------add
-7y = 7
y = -1
<span>4x−3y=15
</span>4x -3(-1) = 15
4x + 3 =15
4x = 12
x = 3
answer: (3, -1)
Answer:
75
Step-by-step explanation:
For non-normal distributions, we use Chebyshev's Theorem.
Chebyshev Theorem
The Chebyshev Theorem states that:
At least 75% of the measures are within 2 standard deviations of the mean.
At least 89% of the measures are within 3 standard deviations of the mean.
An in general terms, the percentage of measures within k standard deviations of the mean is given by .
In this question:
Within 2 standard deviations of the mean, so 75%.
The big one is 603.2 the middle one is 282.7 and the small one is 100.5
Answer: see proof below
<u>Step-by-step explanation:</u>
Given: cos 330 =
Use the Double-Angle Identity: cos 2A = 2 cos² A - 1
Proof LHS → RHS:
LHS cos 165
Double-Angle: cos (2 · 165) = 2 cos² 165 - 1
⇒ cos 330 = 2 cos² 165 - 1
⇒ 2 cos² 165 = cos 330 + 1
Given:
Divide by 2:
Square root:
Scratchwork:
Since cos 165 is in the 2nd Quadrant, the sign is NEGATIVE
LHS = RHS