Answer:
i) 28 - 30i
ii) 36 + 28i
Step-by-step explanation:
i) x = 6 + i ⇒2x = 2(6 + i) = 12 + 2i
z = 4 - 8i ⇒ 4z = 4(4 - 8i) = 16 - 32i
2x + 4z = (12 + 2i) + (16 - 32i) = 28 - 30i
ii) w = -1 + 5i and z = 4 - 8i
w × z = (-1 + 5i)(4 - 8i) = -4 + 8i + 20i - 40
⇒collect like terms
w × z = -4 + 28i - 40![i^{2}](https://tex.z-dn.net/?f=i%5E%7B2%7D)
∵ ![i^{2}=-1](https://tex.z-dn.net/?f=i%5E%7B2%7D%3D-1)
∴w × z = -4 + 28i - 40(-1) = -4 + 28i + 40 = 36 + 28i
The question is asking us to find the value of x and to round it to the nearest tenth. We know that x^2 = 112. Therefore: x = sqrt ( 112 ); x = 10.583. And also we have to round it to the nearest tenth. we can see that the digit on the place of hundredths is 8 ( which is greater than 5 ). So we add 1 to the tenths place: x = 10.6. Answer: <span>10.6.</span>
Let's say x to the daughter's age, since the father's age is four times the daughter's age, his age will be 4x. 18 years later, the daughter's age will be x+18 and the father's will be 4x+18. And we know that 18 years later the father's age will be twice the daughter' so , 4x+18 = 2(x+18) and 4x+18=2x+36 then, 4x-2x=36-18,
2x=18 then divide both sides by 2, x = 9. The daughter's age was x, so she is 9 years old.
Answer:
rational
Step-by-step explanation:
![\sqrt{42.25} \\ \\ = 6.5 \\ \\ = \frac{65}{10} \\ \\ = \frac{13}{2} \:this \: is \: a \: rational \: number \\ \implies \: \sqrt{42.25} \: is \: also \: rational](https://tex.z-dn.net/?f=%20%5Csqrt%7B42.25%7D%20%20%5C%5C%20%20%5C%5C%20%20%3D%206.5%20%20%20%5C%5C%20%5C%5C%20%3D%20%20%5Cfrac%7B65%7D%7B10%7D%20%20%20%5C%5C%20%20%5C%5C%20%3D%20%20%5Cfrac%7B13%7D%7B2%7D%20%20%5C%3Athis%20%5C%3A%20is%20%5C%3A%20a%20%5C%3A%20rational%20%5C%3A%20number%20%5C%5C%20%20%5Cimplies%20%5C%3A%20%20%5Csqrt%7B42.25%7D%20%20%5C%3A%20is%20%5C%3A%20also%20%5C%3A%20rational)
Answer:
A because both teachers and students Prefer Logo A