Quadratic formula: [tex]x=\frac{-b+/-\sqrt{b^2-4ac} }{2a}[/tex] [ +/- is ± ]
You can find the value of a, b, c --> ax² + bx + c = 0
[tex]x=\frac{-2+/-\sqrt{2^2-4(1)(-4)} }{2(1)}[/tex] Since this is not simplified, you can find a, b, c:
a = 1
b = 2
c = -4
A.) x² + 1 = 2x − 3 Make the equation into ax² + bx + c = 0. Subtract 2x on both sides, and add 3 on both sides to set the equation equal to 0
x² + 1 - 2x + 3 = 2x - 2x - 3 + 3
x² - 2x + 4 = 0
a = 1
b = -2
c = 4 This is not the answer because b = 2 not -2, and c = -4 not 4
B.) x² - 2x − 1 = 3 Subtract 3 on both sides to set the equation = 0
x² - 2x - 4 = 0
a = 1
b = -2
c = -4 This is not the answer because b = 2 not -2
C. x² + 2x - 1 = 3 Subtract 3 on both sides to set the equation = 0
x² + 2x - 4 = 0
a = 1
b = 2
c = -4 This is your answer
D. x² + 2x - 1 = -3 Add 3 on both sides to set the equation = 0
x² + 2x + 2 = 0
a = 1
b = 2
c = 2 This is not the answer because c = -4 not 2
