`a)2(x-2)(x+2)-10(x+5)`
`=2(x^2-4)-10x-50`
`=2x^2-8-10x-50=2x^2-10-58`
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`b)4(x-1)(x+5)-(2x+1)(x+5)`
`=4x^2+20x-4x-20-2x^2-10x-x-5`
`=2x^2+5x-25`
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`c)(-3x-1)(x+2)+(3x-6)(x+5)`
`=-3x^2-6x-x-2+3x^2+15x-6x-30`
`=2x-32`