(-b)的8次方÷(-b)＝(-b)的7次方=-b的7次方
(ab)的4次方÷(ab)²＝a²b²
若2的x次方=32分之1,
2^x=2^(-5)
x=-5
则x²＝25
若x的2m次方÷x²＝x的6次方,
x^(2m-2)=x^6
2m-2=6
则m＝4,
计算32的m次方÷8的m次方×4结果为
=8^m×4^m÷8^m×4
=4^(m-1)
已知x+y=10,xy=4,则x²+y²=(x+y)²-2xy=10²-8=92,
用提公因式法5a(x-y)-10b(y-x),提出公因式是,5(x-y)
5a(x-y)-10b(y-x)
=5a(x-y)+10b(x-y)
=5(x-y)(a+2b)
计算(-2x-1)²＝4x²+4x+1