What is 2/8 plus 3/8 plus 4/8?
2 answers:
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Answer:
A
Step-by-step explanation:
We have the expression:
And we want to find its sign given that a>0 and b<0.
Notice that the expression is already negative since we have -4.
a>0 means that a is positive. Therefore, we can ignore it since it won’t do anything.
b<0 means that b is negative. Therefore, we will have two negatives being multiplied together. Hence, this will make a positive.
Therefore, the sign of our expression will be positive.
We can see this with an example. Let a=1 (1>0) and let b=-1 (-1<0). Then:
So, the sign is positive.
Hence, the answer is A.
Answer:
Second choice:
Fifth choice:
Step-by-step explanation:
Let's look at choice 1.
I'm going to subtract 1 on both sides for the first equation giving me . I will replace the
in the second equation with this substitution from equation 1.
Expand using the distributive property and the identity :
So this not the desired result.
Let's look at choice 2.
Solve the first equation for by dividing both sides by 2:
.
Let's plug this into equation 2:
This is the desired result.
Choice 3:
Solve the first equation for by adding 3 on both sides:
.
Plug into second equation:
Expanding using the distributive property and the earlier identity mentioned to expand the binomial square:
Not the desired result.
Choice 4:
I'm going to solve the bottom equation for since I don't want to deal with square roots.
Add 3 on both sides:
Divide both sides by 2:
Plug into equation 1:
This is not the desired result because the variable will be squared now instead of the
variable.
Choice 5:
Solve the first equation for by subtracting 1 on both sides:
.
Plug into equation 2:
Distribute and use the binomial square identity used earlier:
.
This is the desired result.
