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Originally Posted by wzartv Number 2, however, I noticed an error.
(-4^2) comes out to -16, not 16.
That is the only error in that problem. Be sure to look over the problem and see where you made that mistake. Try working it out again and the answer is -8. |
Let me just add to this...
(-4^2) = -(4^2) = -16
but...
((-4)^2) = 16
Just watch out how the braces are placed.
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Originally Posted by wzartv Number 3, I noticed an error.
The variables in the problem (x and y) have a negative sign in front of them. Also, the numbers that are replacing the variables are negative. That's a double negative, therefore making them a positive number. Look at the problem, see what I mean, and the answer comes out to 17, not -17. |
I have to dissagree here.
Let's look at the braces again...
-x^2-y^3 if x=-3 y=-2
that means...
-(x^2)-(y^3) = - ((-3)^2) - ((-2)^3) = -9 - (-8) = -9 + 8 = -1
You have to be careful with the braces.
About the 4th problem...
a^2-b^2a if a=-2 b=3
Let's imagine that you misstyped "-b^2a" and that it should be "-b^2".
a^2 - (b^2) = (-2)^2 - (3^2) = 4 - 9 = -5
Let's imagine that you didn't misstype that...
You have multiple options...does that mean
- (b^(2a))........................(case 1)
or does it mean
- (b^2)*a.........................(case 2)
Case 1:
-(b^(2a)) = - (3^(2*(-2))) = - (3^(-4)) = - ( 1 / (3^4) ) = - ( 1 / 81 )
Case 2:
- (b^2)*a = - (3^2) * (-2) = (-9) * (-2) = 9 * 2 = 18
So the whole result in case 1 would be "4 - ( 1 / 82 )" and in case 2 "4 + 18 = 22"
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