Answer: A, B, C, and E
Step-by-step explanation:
If both sides are real numbers, then the product will be a real number.
If in at least one of the sides we have a complex number, then the product will be real if:
The other number is zero.
The other number is the conjugate of the first.
This is when:
Suppose we have a number:
z = a + b*i
The conjugate will be:
w = a - b*i
And the product between them is:
(a + b*i)*(a - b*i) = a^2 + a*b*i - a*b*i + b^2 = a^2 + b^2
Then the options that will have a real answer are:
A. (4+5i)(4-5i) = 4^2 + 5^2 = 16 + 25 = 41
B. (4 + 91)*(41 - 9) = 3040
C. (3 + 2*i)*(3 -2*i) = 3^2 + 2^2 = 9 + 4 = 13
E. (312 + 7i)*(312 - 7i) = 312^2 + 7^2 = 97,393
Answer:
a) 9yd
b) 12ft
Step-by-step explanation:
a) find the square root
b) divide 48 by 4
Answer:
c=3
Step-by-step explanation:
First simplify like terms.
1+4c=7+2c
1+2c=7 (subtract 2c from both sides)
2c=6 (subtract 1 from both sides)
c=3 (divide by 2)
CHECK:
1+4(3)=7+2(3)
1+12=7+6
13=13
Yes!
Answer:
11.176 meters/second
Step-by-step explanation:
1 mile = 1609.34 meters
25 miles = 40233.6 meters
1 hour = 60 minutes
1 minute = 60 seconds
1 hour = 3600 seconds
40233.6 / 3600,
11.176 meters/second
Answer:
Step-by-step explanation:
13 and 4 in some combination.
The larger number must be minus.
The answer is - 13 + 4 which leaves you with - 9