We have,
tanα=11+2−x and tanβ=11+2x+1
Now, tan(α+β)=tanα+tanβ1−tanα×tanβ
=11+2−x+11+2x+11−11+2−x×11+2x+1
=1+2x+1+1+2−x(1+2−x)(1+2x+1)1−1(1+2−x)(1+2x+1)
=2+2x+1+1+2−x(1+2x+1+2−x+2)1−11+2x+1+2−x+2
=2+2x+1+2−x3+2x+1+2−x1−13+2x+1+2−x
=2+2x+1+2−x3+2x+1+2−x3+2x+1+2−x−13+2x+1+2−x
=2+2x+1+2−x2+2x+1+2−x
=1
⇒tan(α+β)=1=tan(π4)
⇒tan(α+β)=tan(π4)
⇒α+β=π4