已知A=3a²-2b²,B=a²+6b².若A=5,B=15,求a²-a²b²+4b²
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![已知A=3a²-2b²,B=a²+6b².若A=5,B=15,求a²-a²b²+4b²](/uploads/image/z/342900-36-0.jpg?t=%E5%B7%B2%E7%9F%A5A%3D3a%26%23178%3B-2b%26%23178%3B%2CB%3Da%26%23178%3B%2B6b%26%23178%3B.%E8%8B%A5A%3D5%2CB%3D15%2C%E6%B1%82a%26%23178%3B-a%26%23178%3Bb%26%23178%3B%2B4b%26%23178%3B)
已知A=3a²-2b²,B=a²+6b².若A=5,B=15,求a²-a²b²+4b²
已知A=3a²-2b²,B=a²+6b².若A=5,B=15,求a²-a²b²+4b²
已知A=3a²-2b²,B=a²+6b².若A=5,B=15,求a²-a²b²+4b²
若A=5,B=15,则
3a²-2b²=5.(1)
a²+6b²=15.(2)
(1)*3+(2):
a^2=3
则b^2=2
a²-a²b²+4b²
=3-3*2+4*2
=5