Question

Solve 2x2 − 6x = −8.

Answer 1

Answer:

Option 4 - the quantity of 3 plus or minus i square root 7 all over 2

Step-by-step explanation:

Given : Expression $2x^2-6x=-8$

To find : The solution of the expression ?

Solution :

Expression $2x^2-6x=-8$ can be written as

$2x^2-6x+8=0$

$x^2-3x+4=0$

Solve by quadratic formula,

The general form of quadratic equation is $ax^2+bx+c=0$ with solution $x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$

On comparing with $x^2-3x+4=0$, a=1 , b=-3, c=4

Substitute in solution,

$x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$

$x=\frac{-(-3)\pm\sqrt{(-3)^2-4(1)(4)}}{2(1)}$

$x=\frac{3\pm\sqrt{9-16}}{2}$

$x=\frac{3\pm\sqrt{-7}}{2}$

$x=\frac{3\pmi\sqrt{7}}{2}$

So, The solution is the quantity of 3 plus or minus i square root 7 all over 2.

Therefore, Option 4 is correct.

Answer 2

2x²-6x+8=0
x²-3x+4=0
D=b²-4ac=9-16=-7
x=(3+/-i√7)/2
correct answer is the last one