1) =0,4х-1+6х+3,6=6,4х+2,6, если х = 0,4, то 6,4*0,4+2,6=5,16
2) =1,5х-1+2,8-4,2х=1,8-2,7х, при х= -0,2 1,8-2,7*(-0,2)= 1,8+0,54=2,34
3)=1,2х-1,8+3,6х-5,4=4,8х-7,2, при х=-0,1 4,8*(-0,1)-7,2=-0,48-7,2=-7,68
4)5-2(3х-4)=4х-3 5)3-4(2х-5)=2-6х 6)6-3 (2х-5)=2х-7
5-6х+8=4х-3 3-8х+20=2-6х 6-6х+15=2х-7
16=10х 21=2х 28=8х
х=1,6 х=10,5 х=3,5
7)9-2(3х-4)=3х+8 8)11+4 (х-3)=9х- 15
9-6х+8=3х+8 11+4х-12= 9х-15
9=9х 14=5х
х=1 х=2,8
= (x⁴-x²+1)(x⁴+x²+1) = (x⁴-x²+1) ( (x²)² +2x²+1² - x² ) =
= (x⁴ -x²+1) ( (x²+1)² - x² ) = (x⁴-x²+1)(x²+1-x )(x²+1+x)=
= (x⁴ -x²+1)(x²-x+1)(x²+x+1)
2) a³-3a+2 = a³ - 1³ -3a+3 = (a-1)(a²+a+1) -3(a-1) =
= (a-1)(a²+a+1-3) = (a-1)(a²+a-2)= (a-1)(a²+2a-a-2) =
= (a-1)(a(a+2) -1(a+2)) = (a-1)(a-1)(a+2) =
= (a-1)²(a+2)
3)x⁴+x²y²+y⁴= (x²)² + 2x²y² +(y²)² - (xy)²=
= (x²+y²)² - (xy)² = (x² +y²- xy)(x²+y²+xy)
4)x³+3x²-4 = x³ +2x² + x² - 2² = x²(x+2) +(x+2)(x-2) =
=(x+2)(x² +x-2) = (x+2)(x² -1 +x-1) = (x+2)( (x-1)(x+1) +1(x-1)) =
= (x+2)(x-1)(x+1+1) = (x+2)²(x-1)