在平面直角坐标系中,已知点A(2a-b,-8)与点B(-2,a+3b)关于原点对称,求a、b的值.
根据题意,得2a-b=2a+3b=8,
解得a=2b=2.
—I promise to go shopping with you if you help me with the housework.
—________ You are the last person to keep a promise.[ ]
A. That's great!
B. Come off it!
C. I don't agree.
D. I don't believe so.
李子怡今年9岁,爸爸今年43岁,子怡几岁时,爸爸的年龄正好是子怡的3倍( )
A.17
B.27
C.7
D.37