metadata
source: ncert
topic: algebra
class_level: class_6
chapter: ch11
difficulty: beginner
Class 6 | Ch11: Algebra - Introduction Variable: letter for unknown (x,y,n). Constant: fixed value. 3x means 3×x. x^2 means x×x. "5 less than x" = x-5 NOT 5-x. Like terms: same variable and power (3x and 7x). Unlike: different. Expression: no equal sign (2x+3). Equation: has equal sign (2x+3=11). Substitution: x=4 in 3x+5 = 3(4)+5=17. "5 added to 3 times x"=3x+5. "y subtracted from 10"=10-y. "Twice a number decreased by 4"=2n-4. An expression has no solution. Only equations can be solved.