Solve the following equation. 2m^2-m-7=0?

Question

Express roots to the nearest hundreth.

Answer 1

2m^2 - m - 7 = 0

m = (-b ± sqrt(b^2 - 4ac))/(2a)

m = (-(-1) ± sqrt((-1)^2 - 4(2)(-7)))/(2(2))
m = (1 ± sqrt(1 + 56))/4
m = (1 ± sqrt(57))/4
m = 2.14 or -1.64

ANS m = 2.14 or -1.64

Answer 2

Complete the square:

2m^2 - m - 7 = 0
2m^2 - m = 7
m^2 - (1/2)m = 7/2
m^2 - (1/2)m + 1/16= 7/2 + 1/16
(m - 1/4)^2= 7/2 + 1/16
(m - 1/4)^2= 56/16 + 1/16
(m - 1/4)^2= 57/16
m - 1/4 = ±sqrt(57/16)
m - 1/4 = ±sqrt(57)/4
m = (1±sqrt(57))/4

Now get out the calculator and finish it.

Answer 3

Use the quadratic formula:
x=-b±√b^2-4ac/2a
a=2,b=-1,c=-7
x=-(-1)±√(-1)^2-4(2*-7)/2(2)
x=(1±√1+56)/4
x=(1±√57)/4

I hope this helps!

Answer 4

Sigh...please learn your quadratic formula:

For quadratic polynomials: y = ax^2 + bx + c

x = (-b +/- sqrt(b^2 - 4ac))/2a

so...a=2, b=-1, c=-7

solve

Answer 5

2m^2-m-7=0
By quadratic formula: m = (-b±√(b^2 - 4ac))/2a
m = 4.27 or -3.27