Question

What are the zeros of the function f(x) = (x+5)(2x-7)?

A. x = -5 and x = 4

B. x = 5 and x = -4

C. x = -5 and x = 8

D. x = 5 and x = -8

Answer 1

the answer is c

Explanation:

to find the zeros set

f

(

x

)

=

0

(

3

x

−

5

)

(

2

x

+

7

)

=

0

equate each factor to zero and solve for x

2

x

+

7

=

0

⇒

x

=

−

7

2

3

x

−

5

=

0

⇒

x

=

5

3

Answer 2

Answer: A

Explanation:

`$$Solve for $x$ :$$(x+5)(2 x-7)=0$$Split into two equations:$$x+5=0 \text { and } 2 x-7=0$$Subtract 5 from both sides: $x=-5$ and $2 x-7=0$ \\Add 7 to both sides: $x=-5$ and $2 x=7$\\Divide both sides by 2:\\Answer:$$x=-5 \text { and } x=(7)/(2)$$`

Rounding up for 2nd zero = 7/2 = 3.5

Therefore, the zeroes of the function (rounded to whole numbers) are x = -5 and x = 4