Question

八年级下数学分解因式

500²—1000x498+498²

已知X+Y=1/2,XY=1/8,求X²+Y²的值

Answer 1

500²—1000x498+498²=500²—2×500x498+498²=(500-498)²=2²=4
X²+Y²=X²+Y²+2XY-2XY=(X+Y)²-2XY=(1/2)²-2×1/8=1/4-1/4=0

Answer 2

500²—1000x498+498²
=(500-498)^2
=2^2
=4
x^2+y^2
=(x+y)^2-2xy
=(1/2)^2-2*(1/8)
=1/4-1/4
=0

Answer 3

5002-1000×498+4982
=5002-2×500×498+4982
=（500-498）2
=22
=4

x2+y2
=x2+2xy+y2-2xy
=(x+y)2-2xy
=(1/2)2-2×(1/8)
=1/4-1/4
0

Answer 4

5002—1000x498+4982=（500+498)2

X2+Y2=（X+Y)2-2XY=0

Answer 5

x²+y²=0
x²+y²=（x+y)²-2xy

Answer 6

500²-1000x498+498²
=500²-2×500x498+498²
=(500-498)²=2²=4
X²+Y²=(X+Y)²-2XY
=1/4-1/4
=0