### Chap 5 Algebra: Putting them Back...

Choose ONE of the following...

(B1) Workbook Challenging Practice (p28, Q21)
Yuliana is n years old now. Yuliana's brother, Erwan is 3 years younger than 2 times her age. The sum of their parents' ages is 1 year more than 3 times the sum of their ages.
(a) Simplify, in terms of n,
(i) Erwan's age
(ii) the sum of the parents' ages
(iii) the sum of the ages of Yuliana, Erwan and their parents

(b) If n = 9, find hte sum of the ages of
(i) Yuliana, Erwan and their parents now
(ii) Yuliana, Erwan and their parents 4 years later

(B2) Workbook Challenging Practice (p29, Q24)
Refer to the diagram in the workbook

The length and breadth of a rectangle are (2y + 1) cam and 3x cm respectively. The base and height of a triangle are (7y + 1) cm and 2x cm respectively.
(a) Find, in terms of x and y,
(i) the area of the rectangle
(ii) the area of the triangle

(b) Subtract the area of rectangle from the area of triangle, expressing your answer in terms of x and y

(ii) If y is a prime number, show that the area of the triangle is always greater than or equal to the area of the rectangle

(B3) Textbook Maths@Work (p102)
Let n be the number. Find the resulting expression after going through each step in order.
{This explains why the final answer to the steps below is predictable}
(a) Add 10 to the number
(b) Multiply the sum by 2
(c) Subtract 4 from the result
(d) Divide the result in (c) by 2
(e) Subtract the number n from the result in (d)
(f) Simplify the expression in (e)

(B4) Textbook Maths@Work
(p108)
Refer to the textbook for the diagram.

(a) Factorise 21ax + 7bx + 6ay + 2by.

In the diagram, ABCD is a rectangle. The Rectangle ABCD is further divided into 4 rectangles by the lines PTQ and RTS. The areas of the 4 rectangles are 21ax, 7bx, 6ay and 2by respectively as shown in the diagram. Find the lengths of AR and DP.

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In pairs, explain clearly how you factorise the given expression and use the answer to solve the problem with video clip(s)
• Recall the learning points and feedback you gathered in the previous exercise - especially the value of working together to produce the clip.