182 Let x = width then y = 6x - 91. P (perimeter) = 2x + 2y = 84 then
2(x) + 2(6x - 91) = 84 | 2x + 12x - 182 =84 | 14x = 84 + 182 | 14x = 266 | x = 19 cm
y = 6x - 91 | y = 6 (19) - 91 | y = 114 - 91 | y = 23 cm
Check: P = 2x + 2y | P = 2(19) + 2(23) | P = 38 + 46 | P = 84 cm (Checked)
Answer:
x = 4 and y = - 5
Step-by-step explanation:
note that the product of a complex number and it's conjugate is real
That is
(a + bi)(a - bi) where a, b are real
= a² - abi + abi - b²i²
= a² + b² ← a real number
For (4 + 5i)(x + yi) to be real
we require (x + yi) to be the conjugate of 4 + 5i , that is 4 - 5i
(4 + 5i)(4 - 5i) ⇒ x = 4 and y = - 5
Yeah the answer is number 5
