Question

Sanjay graphs a quadratic function that has x-intercepts of –3 and 7. Which functions could he have graphed?

Answer 1

we will select each options and find zeros

(a)

$g(x)=x^2-4x-21$

for finding x-intercept , we can set g(x)=0

and then we can solve for x

$g(x)=x^2-4x-21=0$

now, we can factor it

$(x-7)(x+3)=0$

we get

$x=7,x=-3$

so, this is TRUE

(b)

$g(x)=(x-3)(x+7)$

we can set it to 0

and then we can solve for x

$g(x)=(x-3)(x+7)=0$

we get

$x=3,x=-7$

so, this is FALSE

(c)

$g(x)=3x^2-12x-63$

we can set it to 0

and then we can solve for x

$g(x)=3x^2-12x-63 =0$

$3(x^2-4x-21) =0$

$3(x-7)(x+3) =0$

$x=-3,x=7$

so, this is TRUE

(d)

$g(x)=-(x+3)(x-7)$

now, we can set it to 0

and then we can solve for x

$g(x)=-(x+3)(x-7)=0$

$x=-3,x=7$

so, this is TRUE

(e)

we have

$g(x)=x^2+4x-21$

now, we can set it to 0

and then we can solve for x

$g(x)=x^2+4x-21=0$

$(x+7)(x-3)=0$

$x=-7,x=3$

so, this is FALSE

Answer 2

Answer:A.  C. D

Step-by-step explanation: