Step-by-step explanation:
AD ≅ BC, Given
∠BCD ≅ ∠ADC, Given
CD ≅ CD, Reflexive property
ΔBCD ≅ ΔADC, SAS congruence
∠BDC ≅ ∠ACD, CPCTC
ΔECD is an isosceles triangle, definition of isosceles
DE ≅ CE, properties of isosceles triangles
150%. since you already have 6, that's 100%. the extra 3 is half of the 6, meaning that it would be 50%
Opposite number is the same number with the opposite sign:
So the opposite of

is

, since the original number is positive
opposite of

is

, since the original number is negative