F1
(7)x2をAと置くと,
(x-2)-9(x-2)+20
=A2-9A+20
=(A-4)(A-5)
={(x-2)-4}{(x-2)-5}
=(x-6)(x-7)
(8) A=2x+3, B=x-6 と置くと,
10
(1)
(2
(3
(4
(2x+3)-(x-6)²
=A²-B²
=(A-B)(A+B)
={(2x+3)-(x-6)}
11 (1
(2
13
14
(5
x{(2x+3)+(x-6)}
=(x+9)(3x-3)
12
11
=3(x+9)(x-1)
(9) (a-b)x-a+b
=(a-b)x-(a-b)
12