Question

Brianna is graphing the function f(x) = x2 + 6x + 5. What x-intercepts should Brianna use to graph f(x)?

–5 and –1
–5 and 1
–1 and 5
1 and 5

Answer 1

@jim_thompson5910 @AlexandervonHumboldt2 @triciaal

Answer 2

an x-intercept is an x value that makes the whole right side equal to 0

Answer 3

so substtute them to the eqaution

Answer 4

like How

Answer 5

let's say someone claims that x = 1 is a root of f(x)

Answer 6

A

Answer 7

that would mean they claim that f(1) = 0

let's find out

f(x) = x^2 + 6x + 5

f(1) = (1)^2 + 6(1) + 5 ... replace every x with 1

f(1) = 1 + 6 + 5

f(1) = 12

the input was x = 1 and the output was y = 12

The output is NOT y = 0, so x = 1 is NOT a root or x-intercept

Answer 8

what are the factors of +5 that add up to +6
1 and 5
so (x+1)(x+5) =0
x = -1 and x = -5