Power of Maths: Paper 1 – Section 2 4 ACTIVITY Y 11 ACTION CTION
Writing linear expressions in the form a x + b
OBJECTIVE To learn how to recognise linear expressions
EXAMPLE 1
Write the following expressions in the form ax + b and read off a and b:
(a) 3x − 2 (b) − 4 + 7x (c) −5x
Solution (a) 3x − 2 is already in this form.
a = 3, b = −2
(b) − 4 + 7x = 7x − 4 a = 7, b = − 4
(c) −5x = −5x + 0 a = −5, b = 0
Expressions
Types of Algebraic
Learning Outcomes earning Outcomes
• To recognise linear and quadratic expressions and to understand how they combine. • To be able to carry out operations on rational expressions of the form a x + b
_____ c x + d
.
• To be able to apply the rules for carrying out operations on exponentials (powers). • To understand how to manipulate surd expressions.
4.1 Linear and quadratic expressions Linear expressions are expressions such as x 1, 2x 1, −3x, 4x + 7 and −5x + 9.
KEY TERM An expression is linear if the highest power of the variable in the expression is 1.
Linear expressions can all be put in the form ax1 + b, where a and b are real constants. a is called the coeffi cient of x and b is called the constant term. TIP
P Get used to writing linear expressions in the form a x + b.
