P(x) = k*(x^2 - 3x + 2) + 4x-7
= k*(x-1)*(x-2) + 4x-7
now the first term is divisible by (x-1) and (x-2). So just check for remainder when (4x-7) is divided by (x-1) and (x-2)
=> 4x-7 = 4(x-1) -3 ........> remainder = -3
=> 4x-7 = 4(x-2) + 1.........>remainder = 1
= k*(x-1)*(x-2) + 4x-7
now the first term is divisible by (x-1) and (x-2). So just check for remainder when (4x-7) is divided by (x-1) and (x-2)
=> 4x-7 = 4(x-1) -3 ........> remainder = -3
=> 4x-7 = 4(x-2) + 1.........>remainder = 1
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(x-1)(x-2) = x^2 -3x + 2,
so if you divide P(x) by this, then the remainder is still 4x-7
so if you divide P(x) by this, then the remainder is still 4x-7
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x^2 -3x + 2 = (x-1)(x-2)