Question

Select the approximate values of x that are solutions to f(x) = 0, where
f(x) = -2x^2 + 5x + 7.

a) {3.50, –1.00}

b) {-2, 5}

c) {–2.50, –3.50}

d) {–0.29, 0.71}

Answer 1

The roots p,q, of the equation
ax²+bx+c=0
have the properties that:
p*q = c/a
p+q =-b/a
Check each of the solution sets above,
c/a=-3.5
If p*q ≠ -3.5, then p and q are not solutions to the equation.
If p*q = -3.5, then check if p+q = -b/a=2.5.
If both conditions are satisfied, p and q form the solution set to the equation.