Math Is Fun Forum

FIND the solution set of the following equation:
X^2-3(modulus x-2)-4=0
Book's Ans:
If x≤2:x^2+3(x-2)-4=0
Therefore x^2+3x-10=0
Therefore x=-5 or 2    ]- ∞,2]
If x>2: x^2-3(x-2)-4=0
Therefore x^2-3x+2=0
therefore x=2 or 1 refused because they  ]2, ∞]
S.S={-5,2}
on wt bases did he put negative signs in the solution ??!
Plzzzzz HELP
sorry i cant write the equation better than that

FIND the Domain :
1. f(x)=square root (x-2) - cubic root (x+3)
2. f(x)=x^2-x-1 ÷ (square root (x-2) - 5)
PLZ explain ur ans

we have now 3 open points on Y-axis so will I say that Range=]-3,-∞] - {0,3}???
hope some1 answer me
SORRY 4 ma bad drawin

In the quadrilateral ABCD , ‹B is bisected by a bisector intersecting  AC(line segment) at E. F is the point of intersection of AD(line segment) with the ray EF drawn parallel to CD(line segment). If AB=9cm , BC=6cm , EF=2.4cm< FIND the length of CD(line segment).

plz attach the drawing to your answer.

prove that:(1-tan²θ)/(1+tan²θ)=2cos²θ-1?