metadata
source: ncert
topic: algebra
class_level: class_7
chapter: ch12
difficulty: beginner
Class 7 | Ch12: Algebraic Expressions Term: single number, variable or product. Like terms: same variable same power. Monomial(1 term), Binomial(2 terms), Trinomial(3 terms), Polynomial(1+ terms). Addition: combine LIKE terms only. (3x^2+2x-5)+(x^2-3x+2)=4x^2-x-3. Subtraction: change sign of ALL terms. (5a+2b)-(2a-3b)=5a+2b-2a+3b=3a+5b. Substitution: 2x^2-3x+1 when x=2: 2(4)-3(2)+1=8-6+1=3. Coefficient: numerical part. In -5xy, coefficient=-5. Degree: sum of powers. 3x^2y has degree 3. 3x+2x^2 CANNOT be simplified (unlike terms). -(2a-3b)=-2a+3b NOT -2a-3b. 3x×2x=6x^2 (multiply coefficients AND add powers).