Find the zeros of f.

f(x) = 2x2 + x − 21

smaller value = ___
larger value = ___

1 answer

F(x) = 2x^2 + x - 21
Y = 2x^2 + x + 1 = 0
A*C Method:
A*C = 2 * (-21 = -42 = -3*14 = -6*7
Choose the pair of factors whose sum = B
-6+7 = 1 = B.
2x^2 + (-6x+7x) - 21 = 0
(2x^2-6x) + (7x-21) = 0
Factor each binomial:
2x(x-3) + 7(x-3) = 0
Factor out (x-3):
(x-3)(2x+7) = 0

x-3 = 0
X = 3.

2x+7 = 0
2x = -7
X = -7/2 = -3.5

Solution set: X = -7/2, and 3.

Note: You may also use the Quadratic Formula.
Similar Questions
    1. answers icon 1 answer
  1. f(x)= x^3 - 2x^2 - 21x - 18all possible rational zeros # of possible positive zeros # of possible negative zeros find all the
    1. answers icon 1 answer
  2. f(x)=x^6+4x^5+4x^4+3x^3-x^2-5x+4Find the maximum number of real zeros, and Use Descartes's rule of signs to determine how many
    1. answers icon 1 answer
  3. find the zeros of f,f(x) = 2x2 + x − 21x= ? larger value x= ? smaller value
    1. answers icon 2 answers
more similar questions