Question

1) If f(x) = 3x2 – Bx + 4 and f(-1) = 12, what is the value of B?

Answer 1

Answer:

$B=-5$

Step-by-step explanation:

we have

$f(x)=3x^{2} -Bx+4$

we know that

f(-1) is the value of the function for x=-1

so

substitute the value of x=-1 in the function and solve for B

$f(-1)=3(-1)^{2} -B(-1)+4$

we have

$f(-1)=12$

substitute

$12=3(-1)^{2} -B(-1)+4$

$12=3-B+4$

$12=7-B$

$B=7-12$

$B=-5$