3+1=4
As all parents would teach their babies simple math...take three candies and take one more. How many candies do you have now? Four
Answer: 0.85 or %85
Fraction = 68 over 80 divide by two twice 17 over
20
Percent = 68/80 = 0.85 x 100 = 85%
Decimal = 0.85
First square both sides to get:
c + 22 = (c + 2)^2
or
c + 22 = c^2 + 4c + 4
Move the terms on the left side to the right side:
c^2 + 3c - 18 = 0
Factor to get:
(c + 6) * (c - 3) = 0.
The solutions are c = -6 and c = 3.
Check to see if these answers work by plugging them into the original equation:
c = -6:
sqrt (-6 + 22) ?= -6 + 2
But, -6 + 2 is a negative number, and you can't get a negative from a square root. So, -6 is extraneous.
c = 3:
sqrt (3 + 22) ?= 3 + 2
5 = 5. So, 3 works.
The answer is: B
A. False. Consider the identity matrix, which is diagonalizable (it's already diagonal) but all its eigenvalues are the same (1).
b. True. Suppose

is the matrix of the eigenvectors of

, and

is the diagonal matrix of the eigenvalues of

:


Then

In other words, the columns of

are

, which are identically

, and these are the columns of

.
c. False. A counterexample is the matrix

which is nonsingular, but it has only one eigenvalue.
d. False. Consider the matrix

with eigenvalue

and eigenvector

, where

. But the matrix can't be diagonalized.