a=12,b=23のとき、次の式の値を求めよ。 4a-6+9b+11 3a+32-5b+73 x=6,y=-8のとき、次の式の値を求めよ。 13x+54y-2x+y (34x+y+12)+(73x-3) m=32,n=-43のとき、次の式の値を求めよ。 -15mn3×(-m4)×2n -16m4n÷(2m2n)2 a=12,b=-4のとき、次の式の値を求めよ。 -821a3b×94ab÷67ab4 57a3÷(-914b2)×154b÷(-52ab4) m=-79,n=143のとき、次の式の値を求めよ。 8m+11n21+2m-13n15 m-n2-3m-4n6+2n a=4,b=-9のとき、次の式の値を求めよ。 12a+3b-4(58a-16b) 12a+b-1-{2a-3b-5(12a+b)}
1. a=12,b=23
①
4a-6+9b+11
=4×12-6+9×23+11
=2-6+6+11
=13
②
3a+32-5b+73
=3×12+32-5×23+73
=32+32-103+73
=3-1
=2
2. x=6,y=-8
①
13x+54y-2x+y
=(13-2)x+(54+1)y
=-53x+94y
=-53×6+94×(-8)
=-10-18
=-28
②
(34x+y+12)+(73x-3)
=(34+73)x+y+12-3
=3712x+y-52
=3712×6-8-52
=372-8-52
=322-8
=16-8
=8
3. m=32,n=-43
①
-15mn3×(-m4)×2n=30m5n4
=30×(32)5×(-43)4
=720
②
-16m4n÷(2m2n)2
=-16m4n÷4m4n2
=-4n
=-4×(-34)
=3
4. a=12,b=-4
①
-821a3b×94ab÷67ab4
=-8a3b×9ab×721×4×6ab4
=-a3b2
=-123(-4)2
=-108
②
57a3÷(-914b2)×154b÷(-52ab4)
=5a37×(-149b2)×15b4×(-25ab4)
=5×14×15×2×a3×b7×9×4×5×b2×ab4
=5a23b5
=5×1223×(-4)5
=-1564
5. m=-79,n=143
①
8m+11n21+2m-13n15
=5(8m+11n)+7(2m-13n)105
=40m+55n+14m-91n105
=54m-36n105
=18m-12n35
={18×(-79)-12×143}×135
=-14-5635
=-7035
=-2
②
m-n2-3m-4n6+2n
=3(m-n)-(3m-4n)+12n6
=3m-3n-3m+4n+12n6
=13n6
=136×143
=919
6. a=4,b=-9
①
12a+3b-4(58a-16b)
=12a+3b-52a+23b
=-2a+113b
=-2×4+113×(-9)
=-8-33
=-41
②
12a+b-1-{2a-3b-5(12a+b)}
=12a+b-1-2a+3b+52a+5b
=(12-2+52)a+(1+3+5)b-1
=a+9b-1
=4-81-1
=-78
