1. Mathsercise-C
Ready?
Using
Formulae
Here we go!

2. Now choose a number between 3 and 4
Use Trial and Improvement to solve..
x3 + 2x = 50 to 1 d.p (x lies between 3 and 4) x
x3 + 2x
Big/small
Question 2 3
= 33
Too small 4
= 72
Too big
3.5 =
Very close!
Now choose a number between 3 and 4
3.6 =
Too big
3.55 =
Too big
Answer
The answer is 3.5 to 1 d.p because the real answer lies between 3.5 and 3.55!
You may be tempted to stop now, but you must go to one more decimal place to prove the answer to 1 d.p 1
Using Formulae

3. 2 Use Trial and Improvement to solve..
½x3 - x = 90 to 1 d.p (x lies between 5 and 6) x
½x3 - x
Big/small
Question 3 5
62.5 – 5 = 57.5
Too small
5.5
Too small
– 5.5 =
5.7
– 5.5 =
Too small
5.8
– 5.5 =
Too Big
5.75
– 5.5 =
Now lets try 5.7
We know that the answer lies between 5 and 6, so now try 5.5
Answer
These are very close, so now try 5.75
This is just under 90, so the real answer must lie between 5.75 and 5.8 or 5.8 to 1 d.p 2
Using Formulae

4. 3 Find the value of…. a) t2 – 4t when t = 3 32 – 4x3 = - 3 9 - 12
Just substitute the values, but be careful with the -4….look at the signs when multiplying!
Find the value of….
a) t2 – 4t when t = 3
Question 4
32 – 4x3
= - 3
9 - 12
Answer
b) p2 – 3p when p = -4
(-4)2 – (3x-4)
16 – (-12)
= 28 3
Using Formulae

5. Another common mistake is that
½ x ½ is not 1!!
Just substitute the values, but be careful with the -2….look at the signs when multiplying!
If P = q2 – 5q……
a) Find P when q = -2
Start
P = (-2)2 – (5x-2)
P = 14
P =
Answer
b) Find P when q = ½
P = (½)2 – (5x½) 4
Using Formulae
P = ¼ – 2.5
P = -2.25