Answer :
Answer:
B
Step-by-step explanation:
using the quadratic formula (formula added) I plugged in all the numbers and solved for x which is the zeros.
ANSWER
The correct choice is B
EXPLANATION
The given function is
[tex]f(x )= 4 {x}^{2} + 5x - 21[/tex]
To find the zeros, we equate the function to zero.
[tex]4 {x}^{2} + 5x - 21 = 0[/tex]
We split the middle term to get:
[tex]4 {x}^{2} + 12x - 7x - 21 = 0[/tex]
Factor by group,
[tex]4x(x + 3) - 7(x + 3) = 0[/tex]
Factor further,
[tex](x + 3)(4x - 7) = 0[/tex]
Use the zero product property,
[tex]x + 3 = 0 \: or \: 4x - 7 = 0[/tex]
[tex]x = - 3 \: or \: x = \frac{7}{4} [/tex]
Hence the zeros are:
B.) {7/4, -3}