Write a two column proof for geometry angle proofs

Given: BF−→− bisects ∠ABC, m∠ABD=m∠CBE

Prove: m∠DBF=m∠EBF

please help me

A33 gram sample of a substance that's used to detect explosives has a k-value of 0.1473. n = noekt no = initial mass (at time t = 0) n = mass at time t k = a positive constant that depends on the substance itself and on the units used to measure time t = time, in days

Witch represents the inverse of the function f(x)=1/4x-12

Acompany that manufactures and sells guitars made changes in their product range. from the start they had 20 models. then they reduced the number of models to 15. as a result, the company enjoyed a 10% increase in turnover. - how much did the stock level change? in (%)