已知-5x+2y=4,则3(5x-2y)²-2(5x-2y)+4(2y-5x)²-20的值为
问题描述：
已知-5x+2y=4,则3(5x-2y)²-2(5x-2y)+4(2y-5x)²-20的值为
答
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∵-5x+2y=4
∴-(-5x+2y)=-4
即5x-2y=-4
∴3(5x-2y)²-2(5x-2y)+4(2y-5x)²-20
=3×(-4)²-2×(-4)+4×4²-20
=3×16+8+64-20
=100