Answer:
3
Step-by-step explanation:
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Answer: r=0.8
Step-by-step explanation:
4r + 8 = 7.2 + 5r
<u> -4r -4r</u>
8=7.2+r
8-7.2=r
0.8=r
Answer:
4x-12
Step-by-step explanation:
2x-5[2x-7(5)}=2x+2x-7-5
4x-12
negative integers are added to each other
There are 12 inches in a foot, so divide 1590 by twelve. It equals 12.5. That is 12 feet and 5 inches!
Answer:
See proof below
Step-by-step explanation:
Let
. If w=-z, then r=0 and r is real. Suppose that w≠-z, that is, r≠0.
Remember this useful identity: if x is a complex number then
where
is the conjugate of x.
Now, using the properties of the conjugate (the conjugate of the sum(product) of two numbers is the sum(product) of the conjugates):

=
Thus
. From this,
. A complex number is real if and only if it is equal to its conjugate, therefore r is real.