Re: inequation
bubblesss said:
so when u substitute to check the value which equation do we sub it in???? the actual question or the most recent one we formed???
sry again for bugging u.
We sub in the maximum/minimum domains into the original question.
ie, for a ≤ x ≤ b, you sub in a and b to make sure the inequality works.
HOWEVER, if it's a < x < b, you need to sub a value abit higher than a, and also a value abit lower than be
For example, some random question - we have as the final answer
2≤x ≤3
You'd sub in x = 2 and x = 3 into the original equation.
but if we have -
2 < x < 3, you'd sub in x = 2.00001 and x = 2.99999 into the original equation.
If we have something like, x < 3/2 and x > 5, same protocol applies. Look out for the equal signs.
I rarely ever check as normally I'm confident with all my working out, and if it works out nicely (mainly does) then you should simply just check if your domains do not make the denominator = 0
Like in your question, we had 2/(2-x) ≥ 3
We know that x =/= 2, so our solution of 4/3 ≤ x ≤ 2 is false as x =/= 2.
So the solution becomes 4/3 ≤ x
< 2