如图,AB⊥BC,∠ABD的度数比∠DBC的度数的2倍少15°,设∠ABD与∠DBC的度数别为x°、y°,根据题意,下列的方程组正确的是( )
A:{x+y=90x=y−15
B:{x+y=90x=2y−15
C:{x+y=90x=15−2y
D:{x+y=90x=2y+15
— Maggie, what you said may result in serious problems.
— I see. I was just telling the truth.
2+7+1=____
6-3+7=____