数学
(1) 2a) (3a-5b)
=20x3a+2ax(-56)
-6a²-10 ab
(14003b)
(2) (2x-74) x (57)
faxa+4ax (-3b) = 2x× (-5x) + (-7Y)X(-5x)
= 42²-12ab
=-10x²+35x4
(3) -b (5a-b)
(4) Za(a-b-c)
=-bx5a + (−b)x(- b) = 2axa+ 2ax(-6) + 2ax (- c)
-5ab + b²
= 2a²-2ab-2ac
(5) (3x +2y +) × (-6x)
= 3xx(-6x)+2yx (-6x)+(1)x(-6x)
-18ײ²-12xy+6x
=
(2) (x295) × (-3x)
=XX(-3X)-24 X (-3x) + 5× (-3x)
= -3x+6xy-15x
15112
2 x XZ X X D
問21
(117774) 3x25
• 2x²2²-8x+3x²+15x
-5₂²²² +7x
154 3
(1) (4xy+6㎜y)÷2×
(4xy² +67Y)X = X
2x
25
24²+3xy
2x²+bx+x²–2x
= 3x² + 4x
(214003-2a 3a 6
-4a²-12a-6a² +12 a
-2a²
(2) (4a²tab)-a
- (4a² + ab) x
40x2+
2+ ax=
- Sa+26
2
a