Write the following as a single fraction in its simplest form - Junior Cycle Mathematics - Question 12 - 2021
Question 12
Write the following as a single fraction in its simplest form.
$$\frac{2}{n - 3} - \frac{5}{2n + 5}$$
Show that $$ (4x - 3)^2 + 24x $$ is positive for all values o... show full transcript
Worked Solution & Example Answer:Write the following as a single fraction in its simplest form - Junior Cycle Mathematics - Question 12 - 2021
Step 1
Write the following as a single fraction in its simplest form.
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Answer
To combine the two fractions, we will use a common denominator. The common denominator is
(n−3)(2n+5).
Rewrite the fractions:
n−32=(n−3)(2n+5)2(2n+5)
and
2n+55=(n−3)(2n+5)5(n−3).
Combine the fractions:
(n−3)(2n+5)2(2n+5)−5(n−3).
Simplify the numerator:
2(2n+5)−5(n−3)=4n+10−5n+15=−n+25.
Thus, we have:
(n−3)(2n+5)−n+25.
In its simplest form, the answer is:
(n−3)(2n+5)−n+25.
Step 2
Show that (4x - 3)^2 + 24x is positive for all values of x ∈ R.
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Answer
To demonstrate that (4x−3)2+24x is positive, we first expand the expression:
Expanding the squared term:
(4x−3)2=16x2−24x+9.
Substituting this back into the expression gives:
16x2−24x+9+24x=16x2+9.
Notice that 16x2 is always non-negative (it is a squared term) and adds a positive value, 9:
16x2+9>0 for all x∈R.
Thus, we can conclude that the entire expression is positive for all real values of x.
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