Page 28 - 新思维数学学生用书8 样章

2 Expressions, formulae

and equations

Getting started

1 Alex thinks of a number, n.
Write an expression for the number Alex gets when
a she multiplies the number by 2

b she adds 5 to the number.
2 Work out the value of p − q when p = 15 and q = 3
3 Simplify these expressions by collecting like terms.

a 3c + 4c + 9d − 2d b 4xy + 7yz − 2xy + zy
4 Expand the brackets.
a 4(x + 3) b 6(2 − 3y)
5 Solve these equations.
a n + 12 = 15 b m − 7 = 2

c 3p = 27 d 2r + 7 = 19
6 Write the inequality shown by this number line.

1 2 3 4 5 6

27