Which change turns the expression $2 n - 5$ into an equation?

Class 6AlgebraAlgebra

Step-by-Step Solution

An equation needs an equals sign joining two expressions, so

2 n - 5 = 9

is one. Substituting a value only evaluates the expression, and extra terms or brackets leave it an expression — none of those add a '='.

Answer: D) Writing

2 n - 5 = 9

To evaluate an expression, **substitute** a value for the variable and compute. If

x = 5

, then

2 x + 3

becomes

2 \times 5 + 3 = 10 + 3 = 13

. The same expression with

x = 0

gives

2 \times 0 + 3 = 3

. Practise substituting — it is the bridge between an algebraic expression and a real number.

Don't just memorise the answer — build a daily practice habit.