Question

Sketch the quadratic function f(x) = x2 + 4x + 3. Which key feature of the graph is given incorrectly?

A) minimum (-2, -1)
B) y-intercept (0, 2)
Eliminate
C) x-intercept (-3, 0)
D) x-intercept (-1, 0)

Answer 1

Answer:B

Explanation:

Answer 2

B

Explanation:

x-intercepts:

factor the function

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

zeros at x=-3,-1

x-intercepts --> (-3,0),(-1,0)

y-intercepts:

set x=0 in f(x)

f(0)=(0)^2+4(0)+3=3

y-intercept --> (0,3)

find minimums and maximums

The max or min of a quadratic function occurs at x=-b/(2a). If a is negative, the max value of the function is f(-b/(2a)). if a is positive, the minimum value of the function is f(-b/(2a)).

f(x)=ax^2+bx+c

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

here a is positive so you are looking for a minimum,

x=-b/(2a)

x=-4/(2*1)

x=-2 ----> plug into f(x), f(-2)=(-2)^2+4(-2)+3=-1

minimum (-2,-1)