Questions I need help with please :)

[lisarae]

1A. (4+7i)-(2-i)

B. (5-2i)(4+4i)

C. (6+3i)(8-4i)

D. (2-6i)(2-6i)

E. (4-9i)(4+9i)

2A. Write a quadradic equation whoes solutions are 3 and -5.

B. A quadradic equation whoes solutions are 3-+6i

C. A quadradic equation whoes solutions are -3/2 and 2/5.

D An equation whoes solutions are -4, 1 and 3.

 

[wjm11]

Please see "Read before posting":

viewtopic.php?f=9&t=12145

A laundry list of problems will generally achieve less than optimal responses. ;-)

Can you show us what you've tried? Share thoughts on problem approaches?

Here's one:

1A. (4+7i)-(2-i)

4-2 = 2
7i-(-i)= 7i + i = 8i

Any thoughts???

 

[fasteddie65]

A. Write a quadradic [sic] equation whoes [sic] solutions are 3 and -5.
The factors will be x - 3 and x + 5. Multiply the factors.
(By the way, it is a QUADRATIC equation.)

B. A quadradic [sic] equation whoes [sic] solutions are 3 ± 6i
x = 3 + 6i and x = 3 - 6i
x - 3 - 6i = 0 x - 3 + 6i = 0
(x - 3 - 6i)(x - 3 + 6i) = 0
To multiply these two factors, treat it as [(x - 3) - 6i] and [(x - 3) + 6i]. Think: difference of squares

C. A quadradic [sic] equation whoes [sic] solutions are -3/2 and 2/5.
x = -3/2 and x = 2/5
2x = -3 5x = 2
2x + 3 = 0 5x - 2 = 0
Multiply 2x + 3 and 5x - 2.

D An equation whoes [sic] solutions are -4, 1 and 3.
There are 3 roots, so there must be 3 factors. (See part A)