Algebra 2 help!!!
posted by Robert on .
What value completes the square for the expression? x2 + 14x
Use the quadratic formula to solve the equation. x2 – 7x – 6 = 0
Simplify the expression. (–2i)(8i)
What are the solutions?
1/2x^2 + 2x + 3 =0
I need help

for number one we see that this could be of the form (x+7)^2 so we expand to get x^2+14x+49 so we need to add 49
for number 2 we can just use the easy way (factoring) although you can use the quad formula. (x1)(x6) to get x=1,6
we multiply coefficients pretending i is a variable. so we get 16 i^2. we know i is the square root of 1 so i^2 = 1. Thus 16 i^2 = 16.
for the last one, multiply both sides by 2x^2 to get 1+2x^3+6x^2. Then we can let y=x^2. Thus we get 1+2y^2+6y and we rearrange terms to get 2y^2+6y+1.
through the quadratic formula etc. we get a complicated nonreal answer: x= (4+2i\sqrt2)/2, (42i\sqrt2)/2