对于数a、b、c、d，规定，< a、b、c、d >＝2ab－c＋d，已知< 1、3、5、x >＝7，求x的值。
20×××××14×××．
直接写出得数：×2= 6×=×=×1=×=+=×=﹣=
计算下面各题．×××．
直接写出得数． 35×=×=×=×= 24×=×=×= 0×=×6=×=×= 24×=
×1= 0×=×1000= 44×=
×
×
×14×
×
×
．
×2= 6×
=
×
=
×1=
×
=
+
=
×
=
﹣
=
×
×
×
．
=
×
=
×
=
×
=
=
×
=
=
×6=
×
=
×
= 24×
=
×1= 0×
=
×1000= 44×
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