the initial statement is:

and then:

So the second statement is false because f should be multiply by e, not by d so is option C)
If you would like to solve (n^3 - n^4) - (3n^3 - 7n^4), you can do this using the following steps:
(n^3 - n^4) - (3n^3 - 7n^4) = <span>n^3 - n^4 - 3n^3 + 7n^4 = n^3 - 3n^3 - n^4 + 7n^4 = -2n^3 + 6n^4
</span>
The correct result would be <span>-2n^3 + 6n^4.</span>
Answer:
Solution : 
Step-by-step explanation:
![-3\left[\cos \left(\frac{-\pi }{4}\right)+i\sin \left(\frac{-\pi \:}{4}\right)\right]\:\div \:2\sqrt{2}\left[\cos \left(\frac{-\pi \:\:}{2}\right)+i\sin \left(\frac{-\pi \:\:\:}{2}\right)\right]](https://tex.z-dn.net/?f=-3%5Cleft%5B%5Ccos%20%5Cleft%28%5Cfrac%7B-%5Cpi%20%7D%7B4%7D%5Cright%29%2Bi%5Csin%20%5Cleft%28%5Cfrac%7B-%5Cpi%20%5C%3A%7D%7B4%7D%5Cright%29%5Cright%5D%5C%3A%5Cdiv%20%5C%3A2%5Csqrt%7B2%7D%5Cleft%5B%5Ccos%20%5Cleft%28%5Cfrac%7B-%5Cpi%20%5C%3A%5C%3A%7D%7B2%7D%5Cright%29%2Bi%5Csin%20%5Cleft%28%5Cfrac%7B-%5Cpi%20%5C%3A%5C%3A%5C%3A%7D%7B2%7D%5Cright%29%5Cright%5D)
Let's apply trivial identities here. We know that cos(-π / 4) = √2 / 2, sin(-π / 4) = - √2 / 2, cos(-π / 2) = 0, sin(-π / 2) = - 1. Let's substitute those values,

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As you can see your solution is the last option.
2x = 8 ... therefore x = 4
4^2 = 16
<span>1. Make y the subject
a) 4y=12x+18
y = 3x + 4.5
b) 2x=7-3y
3y = -2x + 7
y = -2/3x + 7/3
2.
a) what is the equation of the line which passes through both (-2,-4) and (6,16)
slope = (16 + 4)/(6 +2) = 20/8 = 2.5
y = mx + b
-4 =2.5(-2) +b
-4 = -5 +b
b = 1
equation
y = 2.5x + 1
b) what is the equation of the line perpendicular to y= 1/2X + 7 passing through point (3,9)
</span>y= 1/2X + 7
slope = 1/2
slope of line perpendicular = -2
passing through point (3,9)
y = mx + b
9 = -2 (3) + b
b = 15
equation
y = -2x + 15