Question

Can someone check this please?

Answer 1

The function f is defined by \[f(x)=9x^2+12x+c\], where c is constant

Answer 2

Given that f(x)=0 has equal roots, find the value of c and hence solve f(x)=0

Answer 3

so I did

Answer 4

f(x) has real roots, therefore b^2-4ac = 0

So: \[12^2-(4)(9)(c)=0\] which eventually leads to me getting
\[36c=144 \] \[c=4\]

Answer 5

your logic is perfectly sound so far :)

Answer 6

I would reword your first line as:

f(x) has equal roots, therefore b^2-4ac = 0

Answer 7

Solving that gives me

\[(3x+2)(3x+2)=0\] so \[x=-2/3\]

Answer 8

yup - all correct

Answer 9

Thanks again! Mind checking one more?

Answer 10

<<--- Sure, but you should post each question separately in the list to the left

Answer 11

this is encouraged so that others have more of a chance of learning from specific question/answer posts rather than one long set of questions and answers

Answer 12

Good point! Will post it across then :)

Answer 13

thx :)