9. negative 10. negative 11. negative 12.negative 13.negative 14. positive 15. positive 16. negative 17. negative 18. positive
Remember x is x and f(x) is same thing as y.
f(5) = 4
It is same thing as saying, when x = 5, y aka f(x) should be 4. Aka the point (5,4)
Let’s look at D, if x =5 then f(x)=5? No, it should equal 4. So this is wrong. It is also not linear. So NOT D
Lets look at C, if x =5 then
1/5(5)+3 =
5/5 + 3 =
1+3 =
4
So, f(x) aka y = 4. Is this correct? Yes when x =5, y indeed should equal 4, but it is not linear. So NOT C
Lets look at B, if x=5 then,
2^5 -28 =
32 - 28 =
4
So, f(x) aka y = 4. Is this correct? Yes when x =5, y indeed should equal 4, AND it is linear SO THE ANSWER IS B
Check A too, it gets y=14 so thats wrong as it is not 4.
Answer:
see the file hope it's helpful to you
Ok, first group x terms
f(x)=(x²+4x)-8
factor out quadratic coefient (no need but that's the step)
f(x)=1(x²+4x)-8
take 1/2 of the linear coefient and square it
4/2=2, (2)²=4
add positive and negative of it insides the parenthasees
f(x)=1(x²+4x+4-4)-8
factor perfect square
f(x)=1((x+2)²-4)-8
distribute
f(x)=1(x+2)²-4-8
f(x)=1(x+2)²-12
and, now if we wanted to find the x intercepts where f(x)=0 then
0=1(x+2)²-12
12=(x+2)²
+/-2√3=x+2
-2+/-2√3=x
x=-2+2√3 or -2-2√3
that is where the x intercept are
and completed square form is
f(x)=(x+2)²-12
