4 problems i need help with ?

Question

studying for review and I can't remember how to do these!!

write 2 linear equations:

y= I x+1/2 I

solve each system of equations:

3x + y - z = 15

x - y + 3z = -19

2x + 2y + z = 4

solve:

x^2 + 16 = 0

4x^2 = 1

Answer 1

(1)

-y < x + 1/2 < y

-y - 1/2 < x < y - 1/2

y = -x - 1/2

y = x + 1/2

(2) - for the systems question, use your calculator and matrices

http://www.algebralab.org/lessons/lesson...

(3)

x² + 16 = 0

x² = -16

-take square root of both sides, but take out a -1 from the -16, so

x = √-1 * √16

x = 4i (i = √-1)

(4)

4x² = 1  (Divide by 4)

x² = 1/4  (Square root each side)

√x² = √1/4

x = 0.5