1.32+38=70
2.160:2=80
3.43*20=860
4.70*7=490
5.80+860-490=450
-----------------------------
1.340*2=680
2.92*3=276
3.203*2=406
4.680-276+406=810
1м=10дм.
Значит 8м 1 дм = 81 дм
81/2=40,5 - длина каждого бруска
1 : 5/8=8 : 5 ( *8)
3/5 : 13/5=3:13 ( * 5)
1/8 : 5/6=6: 40 ( *48)
0,7:0,02=35:1 (7/10 : 1/50=(7*5)/50 : 1/50=35 : 1)
2 5/6 : 3 1/4=17/6 : 13/4=(17*12)/6 : (13*12)/4=(17*2) : (13*3)=34:39
0,06м --5 см--- ,04 дм--- 30 мм
1.
1) m³+27n³=(m+3n)(m²-3mn+n²)
2) x³-64xy²=x(x²-64y²)=x(x-8y)(x+8y)
3) -3a²+18a-27=-3(a²-6+9)=-3(a-3)²
4) 2ab+10b-2a-10=2ab-2a+10b-10=2a(b-1)+10(b-1) (2a+10)(b-1)
5)a^4-16=a^4-2^4=(a-2)(a+2)(a²+4)
2.
(2a-1)(4a²+2a+1)=a³-1³=a³-1 , a=-1/2
-(1/2)³-1=-1/8-1=-1 1/8
3.
x²-y²+x-y=x²+x-y²-y=x(x+1)-y(y+1)
4x²-4xy+y²-9=(2x-y)²-9=(2x-y-3)(2x-y+3)
ac^4-c^4-ac²+c²=c^4(a-1)-c²(a-1)=(c^4-c²)(a-1)=c²(c²-1)(a-1)
4-m²+2mn-n²=-4+m²-2mn+n²=-4+(m-n)²=(m-n)²-4=(m-n-2)(m-n+2)
4.
1) 6x³-24x=0
6x(x²-4)=0
6x=0 x²-4=0
x1=0 x²=4
x2=2
x3=-2
2) 25x³-10x²+x=0
x(25x²-10x+1)=0
x1=0 25x²-10x+1=0
D=100-4*25*1=0
x2=10/(2*25)
x2=0.2
3) x³-4x² -9x+36=0
x²(x-4)-9(x-4)=0
(x²-9)(x-4)=0
x²-9=0 x-4=0
x²=9 x1=4
x2=3
x3=-3
5.
2^12+5³=4096+125=4221
4221:21=201
4200:21+21:21=200+1=201
6.
a+b=5 ab=-2 a=5-b
(a-b)²=a²-2ab+b²=a²+b²-2ab= (5-b)² -b²-2*(-2)=25-10b+b²-b²+4 =29-b