Question

LHS=(x+a)(x+b) Explaine ​

Answer 1

Consider the equality (x + 1) (x +2) = x2 + 3x + 2. One can evaluate both sides of this equality for some value of a, say x = 5. For x = 5,

LHS = (x + 1) (x + 2) = (5 + 1) (5 + 2) = 6 × 7 = 42

RHS = x2 + 3x + 2 = 52 + 3 × 5 + 2 = 25 + 15 + 2 = 42