x/20 = 21/14 (similar proportions)
x/20 = 3/2 (simplify by canceling out a factor of 7)
x = 30
Answer:
Step-by-step explanation:
Given expression is,
(2x - 1)² + 2(2x - 1) = (2x - 1)(2x + 1)
To prove this identity we will take the left hand side of the equation and will prove equal to the right side.
(2x - 1)² + 2(2x - 1) = (2x - 1)(2x + 1)
4x² - 4x + 1 + 4x - 2 = (2x - 1)(2x + 1)
4x² - 1 = (2x - 1)(2x + 1)
(2x - 1)(2x + 1) = (2x - 1)(2x + 1) [Since a² - b² = (a - b)(a + b)]
Number 1: (-1+2i)+(6-9i)

Number 2: (3-3i)-(4+7i)

Number 3: (-5+2i)+(-2+8i)

To divide 343 by 9, you will use the division algorithm.
The reason is because 343 is not divisible evenly by nine.
You know this because the sum of the digits, 3+4+3 or 10, is not evenly divisible by 9.
Therefore, 343 is not evenly divisible by 9.