Answer/Discussion
to 1a
-7
The opposite of -7 is 7, since -7 + 7 = 0.
The reciprocal of -7 is -1/7, since -7(-1/7) = 1.
Answer/Discussion
to 1b
3/5
The opposite of 3/5 is -3/5, since 3/5 + (-3/5) = 0.
The reciprocal of 3/5 is 5/3, since (3/5)(5/3) = 1.
Answer/Discussion
to 2a
xy
Using the commutative property of multiplication (where changing the order of a product does not change the value of it), we get
xy = yx
Answer/Discussion
to 2b
.1 + 3x
Using the commutative property of addition (where changing the order of a sum does not change the value of it), we get
.1 + 3x = 3x + .1
Answer/Discussion
to 3a
(a + b) + 1.5
Using the associative property of addition (where changing the grouping of a sum does not change the value of it), we get
(a + b) + 1.5 = a + (b + 1.5)
Answer/Discussion
to 3b
5(xy)
Using the associative property of multiplication (where changing the grouping of a product does not change the value of it), we get
5(xy) = (5x)y
Answer/Discussion
to 4a
-2(x - 5)
Answer/Discussion
to 4b
7(5a + 4b + 3c)
Answer/Discussion
to 5a
2(x + 3) - 3x + 4
*Reverse distributive prop with x
Answer/Discussion
to 6a
The difference of x and 5 is greater than
or equal to 7.
Difference translates into subtraction.
Is greater than or equal to will need to be replaced by the symbol >.
Let's put everything together going left to right:
The difference of x and 5 is greater
than or equal to 7.
x - 5 > 7
Answer/Discussion
to 6b
Twice the sum of y and 3 is the opposite
of 10.
Twice translates as 2 times and sum converts to addition.
The word is will be replaced by an =.
The opposite of 10 is -10.
Let's put everything together going left to right:
Twice the sum of y and 3 is the opposite
of 10.
2(y + 3) = -10
Answer/Discussion
to 6c
The product of -3 and x is not equal to
the reciprocal of 9.
Product translates as multiplication.
Is not equal to requires the symbol 
.
The reciprocal of 9 is 1/9.
Let's put everything together going left to right:
The product of -3 and x is not equal to the reciprocal of 9.
Answer/Discussion
to 6d
The quotient of x and 11 is less than - 4.
Quotient translates as division.
The phrase less than will be replaced by the symbol <.
Let's put everything together going left to right:
The quotient of x and 11 is less than - 4.
Answer/Discussion
to 7a
Two angles are complimentary if the sum of their measures is 90 degrees. If the measure of one angle is x degrees, represent the measure of the other angle as an expression of x.
Let's think about this for a second. Let's pretend that one of our angles is 70 degrees. What would be the measure of the other angle if they had to add to be 90? If you said 20, you are correct!
The thought behind how we got that 20 is, the total of 90 is given, we have already used 70, so we would subtract 70 from 90 and that would tell us what the complimentary angle would have to be.
So, using x, we can write an expression that shows that we take the total of 90 and subtract the given angle of x:
90 - x
Answer/Discussion
to 8a
½ ? .5
Since ½ written in decimal form is .5, then 1/2 equals .5:
½ = .5
Answer/Discussion
to 8b
-3.5 ? 1.5
Since -3.5 is to the left of 1.5 on the number line, then -3.5 is less than 1.5:
-3.5 < 1.5
Answer/Discussion
to 8c
4.3 ? 4.21
Since 4.3 is to the right of 4.21 on the number line, then 4.3 is greater than 4.21:
4.3 > 4.21
Last revised on June 11, 2011 by Kim Seward.
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