Math: 70753f99

ID: 70753f99

(SAT Suite Question Bank > Find Questions > Assessment: SAT + Test: Math + Domain: Advanced Math)

Comment: Just about any method will do, so pick one and go with it.

Method 1: Because a parabola will have a vertical axis of symmetry and the two zeroes are more or less given, split the difference between them.

0 = (x + 3)(x + 1)

x = -3 and -1

(-3 + -1)/2 = -2

The correct answer is (B).

Method 2: Use Desmos to graph the function, highlight the x-coordinate of the vertex, then select the answer.

The graph clearly shows that -2 is the answer, so the correct interval must have -2 in it. The only one that does is (B), so the correct answer is (B).

Method 3: You could also multiply the two binomials to put the equation in standard form. The x-value of the vertex will be -b/2a in y = ax^2 + bx + c.

f(x) = (x + 3)(x + 1)

f(x) = x^2 + 4x + 3

x-vertex: -(4)/2(1) = -4/2 = -2

The correct answer is (B).