Question

Use the quadratic equation y = –2x^2 + 4x +5 to complete the statements.

Answer 1

x=2.87083

Explanation:

y = –2x^2 + 4x +5

ax^2 + bx + c = 0

a= -2

b= 4

c= 5

Quadratic formula: x= -b±√b^2-4ac over 2a

1. plug in the numbers

2. x= -4 ± √4^2 -4(-2)(5) over 2(-2)

3. x= -4 ± √16+40 over -4

4. x= -4 ± √56 over -4

next simplify ratidal

x= -4 ± √2·2·2·7 over -4

x= -4 ± 2√2·7 over -4

x= -4 ± 2√14 over -4

divide both sives over four

x= -4 over -4 ± 2√14 over -4

x= -1 over -1 ± √14 over -2

answer:

x=2.87083