The sum of squares of all the real solutions of the equation log(x+1)(2x2+5x+3)=4–log(2x+3)(x2+2x+1) is equal to ________. [2026]
(2)
log(x+1)(2x2+5x+3)=4–log(2x+3)(x2+2x+1)
⇒ log(x+1)[(x+1)(2x+3)]=4–log(2x+3)[(x+1)(x+1)]
⇒ log(x+1)(x+1)|log(x+1)(2x+3)=4–log(2x+3)(x+1)2
⇒ log(x+1)(2x+3)=4–log(2x+3)(x+1)
⇒ log(x+1)(2x+3)+2log(2x+3)(x+1)–3=0
Let t=log(x+1)(2x+3), then log(2x+3)(x+1)=1t
⇒ t+2t–3=0
⇒ t2–3t+2=0 ⇒ (t–1)(t–2)=0
Case (i), t = 1;
log(x+1)(2x+3)=1
⇒ x+1=2x+3 ⇒ x=–2
For log(x+1),(x+1)>0
Let x + 1 = –1, which is invalid.
Case (ii), t = 2;
log(x+1)(2x+3)=2
⇒ x2+2x+1=2x+3 ⇒ x2=2
⇒ x=±2
⇒ x=2 (valid)
⇒ x=–2 (invalid)
∴ Sum of square of all real solution = (2)2=2