1. a11=a1+10d.
a11=-3+7=4.
2. a20=a1+19d.
a20=18-19•0.5=8.5
3. a5=a1+4d.
a5=20+4•3=32.
4. a21=a1+20d.
a21=5.8-20•1.5=-25.8
1. 83/13-2 5/13=83/13- (2×13+5)/13=(83-31)/13=52/13=4
2. 1 2/5 ÷4=(7×1)/(5×4)=7/20=0.35
3. (3.48+1.4-0.48)×2=4,4×2=8.8
4. 4×(2.2-3.6+1.8)=4×0.4=1.6
3/5×22/3=3/5×(2 · 3 + 2)/3=3/5×8/3=(3 · 8)/(5 · 3)=24/15=(8 · 3)/(5 · 3)=8/5=13/5 = 1.6
1.6-4=-2.4
2.7×10'2-0.3×10'3=2.7×100-3.0×1000=270-300=-30
K-y)^2=2k-2y
(k+7)^2=2k+14
(2k-5)^2=4k-25
(4k+3y)^2=16k+9y
(k2-5y)^2=4k-25y
<span>2.
</span>(*+*)^2=36m^2+*+49n^2
<span>(6m+7n)^2=36m^2+2*6m*7n+49n^2=36m^2+84mn+49n^2</span>
Вот. Надеюсь, это поможет тебе