Indices - Quiz 3


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Indices - Quiz 3 Question

Question 1

Which of the following simpliﬁes $-2 u- 1 uv × -v--?$

Not correct. Choice (a) is false.

Try again, you have not used the index laws correctly

Not correct. Choice (b) is false.

Try again, remember $u× u-1 = 1.$

Not correct. Choice (c) is false.

Try again, remember $v-2 × 1 = v-2-1 = v-3. v$

Your answer is correct.

$- 1 uv-2 × u--= u × u-1 × v-2 × 1 = u1- 1v- 2- 1 = u0v-3 = v- 3. v v$

Question 2

Which of the following gives the correct value of $a-1 + b-2$ where $a = 2$ and $b = 3.$

Your answer is correct.

$a-1 + b-2 = 1+ 1-= 9-+-2= 11-. 2 32 18 18$

Not correct. Choice (b) is false.

Try again, recall $a-1 = 1-, a$ not $- a.$

Not correct. Choice (c) is false.

Try again, recall $a-1$ means $1 --. a$

Not correct. Choice (d) is false.

Try again, recall to add fractions you must ﬁnd a common denominator.

Question 3

Which of the following correctly simpliﬁes $x2x4 ? x-7$

Not correct. Choice (a) is false.

Try again, remember $-1--= x7. x-7$

Your answer is correct.

$2 4 x-x- = x2+4-(- 7) = x13 . x-7$

Not correct. Choice (c) is false.

Try again, you have not applied the index laws correctly.

Not correct. Choice (d) is false.

Try again, you have not applied the index laws correctly.

Question 4

Which of the following correctly simpliﬁes $x 75 6√x ---7--? x6$

Not correct. Choice (a) is false.

Try again, remember $1 7 -7-= x-6 . x6$

Not correct. Choice (b) is false.

Try again, you have not applied the index laws correctly or added fractions together correctly.

Not correct. Choice (c) is false.

Try again, you have not applied the index laws correctly or added fractions together correctly.

Your answer is correct.

$75 6√- 75 16 x--7x-= x-x7--= x75+16- 76 = x 25 . x6 x6$

Question 5

Suppose the geometric mean of ${X1,X2 ,... ,Xn}$ is deﬁned by $--- 1 XG = (X1 × X2 × ...×Xn) n .$
Which of the following is the geometric mean, $--- XG ,$ of ${2 ,4 ,3,5,2},$ correct to 2 decimal places?

Not correct. Choice (a) is false.

Try again, you have divided by 5, not taken the 5th root.

Not correct. Choice (b) is false.

Try again, you have only taken the 4th root of the product, not the 5th root.

Not correct. Choice (c) is false.

Try again, you have found the average.

Your answer is correct.

$√ --------------- √--- 52× 4 × 3× 5× 2 = 5240 = 2.993 = 2.99$ correct to 2 decimal places.