(a) ( z − 1 ) 2 − 3 ( z − 3 ) (z-1)^2 - 3(z-3) ( z − 1 ) 2 − 3 ( z − 3 )
Step 1: Expand ( z − 1 ) 2 (z-1)^2 ( z − 1 ) 2 .
( z − 1 ) 2 = z 2 − 2 z + 1 (z-1)^2 = z^2 - 2z + 1 ( z − 1 ) 2 = z 2 − 2 z + 1
Step 2: Expand 3 ( z − 3 ) 3(z-3) 3 ( z − 3 ) .
3 ( z − 3 ) = 3 z − 9 3(z-3) = 3z - 9 3 ( z − 3 ) = 3 z − 9
Step 3: Subtract.
z 2 − 2 z + 1 − ( 3 z − 9 ) = z 2 − 2 z + 1 − 3 z + 9 z^2 - 2z + 1 - (3z - 9) = z^2 - 2z + 1 - 3z + 9 z 2 − 2 z + 1 − ( 3 z − 9 ) = z 2 − 2 z + 1 − 3 z + 9
= z 2 − 5 z + 10 = z^2 - 5z + 10 = z 2 − 5 z + 10
Simplified: z 2 − 5 z + 10 z^2 - 5z + 10 z 2 − 5 z + 10
z 2 − 5 z + 10 \boxed{z^2 - 5z + 10} z 2 − 5 z + 10
(b) x 2 − 5 x + 6 = 0 x^2 - 5x + 6 = 0 x 2 − 5 x + 6 = 0
Step 1: Sum of roots formula: − b a -\frac{b}{a} − a b .
a = 1 a=1 a = 1 , b = − 5 b=-5 b = − 5
− − 5 1 = 5 -\frac{-5}{1} = 5 − 1 − 5 = 5
Step 2: Product of roots formula: c a \frac{c}{a} a c .
c = 6 c=6 c = 6
6 1 = 6 \frac{6}{1} = 6 1 6 = 6
Sum = 5 = 5 = 5 , Product = 6 = 6 = 6
S u m = 5 , P r o d u c t = 6 \boxed{Sum = 5, Product = 6} S u m = 5 , P r o d u c t = 6
(c) 2 x 2 + 3 x − 2 = 0 2x^2 + 3x - 2 = 0 2 x 2 + 3 x − 2 = 0
Step 1: Quadratic formula: x = − b ± b 2 − 4 a c 2 a x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} x = 2 a − b ± b 2 − 4 a c .
a = 2 a=2 a = 2 , b = 3 b=3 b = 3 , c = − 2 c=-2 c = − 2
Step 2: Discriminant D = b 2 − 4 a c D = b^2 - 4ac D = b 2 − 4 a c .
D = 3 2 − 4 ( 2 ) ( − 2 ) = 9 + 16 = 25 D = 3^2 - 4(2)(-2) = 9 + 16 = 25 D = 3 2 − 4 ( 2 ) ( − 2 ) = 9 + 16 = 25
D = 5 \sqrt{D} = 5 D = 5
Step 3: Roots.
x = − 3 ± 5 4 x = \frac{-3 \pm 5}{4} x = 4 − 3 ± 5
x 1 = − 3 + 5 4 = 2 4 = 1 2 x_1 = \frac{-3 + 5}{4} = \frac{2}{4} = \frac{1}{2} x 1 = 4 − 3 + 5 = 4 2 = 2 1
x 2 = − 3 − 5 4 = − 8 4 = − 2 x_2 = \frac{-3 - 5}{4} = \frac{-8}{4} = -2 x 2 = 4 − 3 − 5 = 4 − 8 = − 2
Roots: x = 1 2 , − 2 x = \frac{1}{2}, -2 x = 2 1 , − 2
x = 1 2 , − 2 \boxed{x = \dfrac{1}{2}, -2} x = 2 1 , − 2
(d) x 2 + 4 x + 4 = 0 x^2 + 4x + 4 = 0 x 2 + 4 x + 4 = 0
Step 1: Quadratic formula: x = − b ± b 2 − 4 a c 2 a x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} x = 2 a − b ± b 2 − 4 a c .
a = 1 a=1 a = 1 , b = 4 b=4 b = 4 , c = 4 c=4 c = 4
Step 2: Discriminant D = b 2 − 4 a c D = b^2 - 4ac D = b 2 − 4 a c .
D = 16 − 16 = 0 D = 16 - 16 = 0 D = 16 − 16 = 0
D = 0 \sqrt{D} = 0 D = 0
Step 3: Root.
x = − 4 ± 0 2 = − 4 2 = − 2 x = \frac{-4 \pm 0}{2} = \frac{-4}{2} = -2 x = 2 − 4 ± 0 = 2 − 4 = − 2
Root: x = − 2 x = -2 x = − 2 (repeated)
x = − 2 \boxed{x = -2} x = − 2
(e) 3 x 2 + 2 x − 1 = 0 3x^2 + 2x - 1 = 0 3 x 2 + 2 x − 1 = 0
Step 1: Quadratic formula: x = − b ± b 2 − 4 a c 2 a x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} x = 2 a − b ± b 2 − 4 a c .
a = 3 a=3 a = 3 , b = 2 b=2 b = 2 , c = − 1 c=-1 c = − 1
Step 2: Discriminant D = b 2 − 4 a c D = b^2 - 4ac D = b 2 − 4 a c .
D = 4 − 4 ( 3 ) ( − 1 ) = 4 + 12 = 16 D = 4 - 4(3)(-1) = 4 + 12 = 16 D = 4 − 4 ( 3 ) ( − 1 ) = 4 + 12 = 16
D = 4 \sqrt{D} = 4 D = 4
Step 3: Roots.
x = − 2 ± 4 6 x = \frac{-2 \pm 4}{6} x = 6 − 2 ± 4
x 1 = − 2 + 4 6 = 2 6 = 1 3 x_1 = \frac{-2 + 4}{6} = \frac{2}{6} = \frac{1}{3} x 1 = 6 − 2 + 4 = 6 2 = 3 1
x 2 = − 2 − 4 6 = − 6 6 = − 1 x_2 = \frac{-2 - 4}{6} = \frac{-6}{6} = -1 x 2 = 6 − 2 − 4 = 6 − 6 = − 1
Roots: x = 1 3 , − 1 x = \frac{1}{3}, -1 x = 3 1 , − 1
x = 1 3 , − 1 \boxed{x = \dfrac{1}{3}, -1} x = 3 1 , − 1