i :
i i= i
i2 = -1
i3 = -i (i x i2)
i4 = 1 (i2 x i2)
Multiplying by i :
Multiplying by i (3+2i) (3-2i) = 9-6i+6i-4i2
Notice how the 6’s will cancel
You are left with 9-4i2
Notice however, that i2=-1.
So you are really left with 9-(4(-1)), or 9+4
The answer to this problem is, 13.
Dividing by i :
Dividing by i Make sure to multiply by the conjugate!!!
3+2i conjugate = 3-2i
-4+5i conjugate = -4-5i The conjugate of 3-2i, is 3+2i, so therefore
multiply both the top and bottom by 3+2i 5(3+2i)
(3-2i)3+2i) You get 15+10i
9-4i2 which equals 13
Rational Expressions :
Rational Expressions Division: a/b, making sure that b doesn’t equal 0. X2-9= (x+3)(x-3)
X2+2x-15= (x+5)(x-3)
The x-3’s will cancel so you are left with
(x+3)
(x+5)
So x, can not equal -5
Multiplying Rationals :
Multiplying Rationals X = X = =