Question

Let f(x)=3−(x+4)+2x. How do you find all values of x for which f(x) is at least 6?

Answer 1

f(x)>6

3-(x+4)+2x>6

x-1>6

x>7

Answer 2

F(x) = 3 - (x+4) + 2x

F(x) = 3 - x-4+2x

F(x) = x - 1

$\rule{200}{2}$

Now,

F(x) must be at least 6.

So,

Value of x for which f(x) becomes 6 is as follows :-

$x - 1 = 6 \\ \\ x = 6 + 1 \\ \\ \\ x = 7$

$\rule{200}{2}$

Thus,

For x = 7, F(x) is equivalent to 6

$\rule{200}{2}$

Hence,

x must be greater than or equal to 7 to get the value of f(x) Which is at least 6.

$\rule{200}{2}$