【简答题】阅读下列解方程组的方法,然后回答问题. 解方程组 19x+18y=17 ① 17x+16y=15 ② 由①-②得2x+2y=2 即x+y=1 ③×16得16x+16y=16 ④ ②-④得x=-1,从而可得y=2 ∴原方程组的解是 x=-1 y=2 . (1)请你仿上面的解法解方程组 2012x+2011y=2010 2010x+2009y=2008 ; (2)请大胆猜测关于x、y的方程组 (...
【简答题】直接写出下面各题的得数. 1 5 + 1 6 = 1 5 - 1 6 = 1 6 + 1 7 = 1 6 - 1 7 = 1 7 + 1 8 = 1 7 - 1 8 = 1 8 + 1 9 = 1 8 - 1 9 =
【简答题】How many inventions and discoveries made by man are mentioned in the passage?
【简答题】如图,已知∠A=∠B,AA 1 ,BB 1 ,PP 1 均垂直于A 1 B 1 ,AA 1 =17,PP 1 =16,BB 1 =20,A 1 B 1 =12 则AP+PB=( )。
【简答题】(4+ 1 5 + 1 6 + 1 7 )×( 1 5 + 1 6 + 1 7 + 1 8 )-(4+ 1 5 + 1 6 + 1 7 + 1 8 )×( 1 5 + 1 6 + 1 7 ) .
【简答题】A.2-15-1 B.2-16-1 C.-1 D.2-17-1
【单选题】Many discoveries are made ____.
【简答题】直接写出得数. 1- 1 2 = 3.2+1.78= 3 5 - 1 6 = 1 3 + 1 2 = 1 6 + 1 7 + 1 5 = 0.48÷120= 1.01×99= 1 7 + 6 7 = 2 3 + 1 6 = 1 6 + 1 2 - 1 6 =
【单选题】把 1 6 、 1 9 、 1 8 、 1 7 按从大到小的顺序排列是( )
【单选题】Many important scientific discoveries are in fact ______ones as they were made by chance.