Question

Find the values of k that make 2x^2 + kx + 5 factorable.

A.
1 or 10

B.
2 or 5

C.
7 or 11

D.
1 or 5

Answer 1

to make x factorable..
the discriminant of "x" should be higher than 0 and should be a perfect square...
the discriminant of a function
ax^2 + bx + c is
b^2 - 4ac

so... ur prob
2x^2 + kx + 5
ax ^2 + bx + c
the discriminant is..
b^2 - 4ac
k^2 -40
and this value should be above 0
which means..
k^2 - 40 > 0
k^2> 0
and
k^2 - 40 should be a perfect square....
the choices that satisfy this conditions r..
7 , 11
hope this will help ya!!!