13.計(jì)算：-4x-3(x+2y)+5y=_______.
14.一個(gè)長(zhǎng)方形的一邊為3a+4b，另一邊為a+b，那么這個(gè)長(zhǎng)方形的周長(zhǎng)為_______.
15.若-5abn-1與 am-1b3是同類項(xiàng)，則m+2n=_______.
16.a是某數(shù)的十位數(shù)字，b是它的個(gè)位數(shù)字，則這個(gè)數(shù)可表示為_______.
17.若A=x2-3x-6，B=2x2-4x+6，則3A-2B=_______
18.單項(xiàng)式5.2×105a3bc4的次數(shù)是_______，單項(xiàng)式- πa2b的系數(shù)是_______.
19.代數(shù)式x2-x與代數(shù)式A的和為-x2-x+1，則代數(shù)式A=_______.
20.已知 ×2= +2， ×3= +3， ×4= +4，…，若 ×10= +10(a、b都是正整數(shù))，則a+b的值是_______.
21.已知m2-mn=2，mn-n2=5，則3m2+2mn-5n2=_______.
22.觀察單項(xiàng)式：2a，-4a2，8a3，-16a4，…，根據(jù)規(guī)律，第n個(gè)式子是_______.
答案
13.-7x-y 14.8a+10b 15.10 16.10a+b
17.-x2-x-30 18. 8 - π
19.-2x2+1 20.19 21.31 22.(-1)n+1 •2nan
14.一個(gè)長(zhǎng)方形的一邊為3a+4b，另一邊為a+b，那么這個(gè)長(zhǎng)方形的周長(zhǎng)為_______.
15.若-5abn-1與 am-1b3是同類項(xiàng)，則m+2n=_______.
16.a是某數(shù)的十位數(shù)字，b是它的個(gè)位數(shù)字，則這個(gè)數(shù)可表示為_______.
17.若A=x2-3x-6，B=2x2-4x+6，則3A-2B=_______
18.單項(xiàng)式5.2×105a3bc4的次數(shù)是_______，單項(xiàng)式- πa2b的系數(shù)是_______.
19.代數(shù)式x2-x與代數(shù)式A的和為-x2-x+1，則代數(shù)式A=_______.
20.已知 ×2= +2， ×3= +3， ×4= +4，…，若 ×10= +10(a、b都是正整數(shù))，則a+b的值是_______.
21.已知m2-mn=2，mn-n2=5，則3m2+2mn-5n2=_______.
22.觀察單項(xiàng)式：2a，-4a2，8a3，-16a4，…，根據(jù)規(guī)律，第n個(gè)式子是_______.
答案
13.-7x-y 14.8a+10b 15.10 16.10a+b
17.-x2-x-30 18. 8 - π
19.-2x2+1 20.19 21.31 22.(-1)n+1 •2nan