问题
填空题
若5-x+2y=2,则x-2y+4的值是______;当n=5时,代数式-8n+5=______.
答案
∵5-x+2y=2,
∵x-2y=5-2=3,
则x-2y+4=3+4=7;
当n=5时,-8n+5=-8×5+5=-35,
故答案为:7,-35.
若5-x+2y=2,则x-2y+4的值是______;当n=5时,代数式-8n+5=______.
∵5-x+2y=2,
∵x-2y=5-2=3,
则x-2y+4=3+4=7;
当n=5时,-8n+5=-8×5+5=-35,
故答案为:7,-35.