Answer:
D
Step-by-step explanation:
Expand factors using FOIL
A
(x + 1)² - x² = x² + 2x + 1 - x² = 2x + 1 ≠ 1 ← False
B
(5x - 2)² + 4 = 25x² - 20x + 4 + 4 = 25x² - 20x + 8 ≠ 25x² - 20x ← False
C
(x + 2y)(x - 2y) = x² - 4y² ≠ x² + 4xy - 4y² ← False
D
(2x + y)(- y - 2x) = - 2xy - 4x² - y² - 2xy = - 4x² - y² - 4xy ← True
Answer:
Step-by-step explanation: How do you find the 3rd angle of a triangle?
Image result for im not sure on how to do this If one angle of a triangle is 30° more than twice another angle, and the third angle is equal to the sum of the first two angles, find the measure of each angle.
The three angles of any triangle add up to 180 degrees. Since you know two angles (35 and 40), add them together, then subtract the total from 180 to determine the degree of the third angle.
Step-by-step explanation:
x²y = k, where k is a real constant.
When x = 3.5, y = 8.
=> (3.5)²(8) = k, k = 98.
When y = 8/9,
we have x²(8/9) = (98).
=> x² = 110.25
=> x = 10.5 or x = -10.5.
Since we want the negative value,
the answer is x = -10.5.
