(3/8)^-1 + 3^-2-(-2,6)^0 = 1:3/8 +1/3^2+1 = 1*8/3 +1/9 +1 = 8/3+1/9+1 = 8/3+1/9+3/3 = (8*3+1*1+3*3)/9 = (24-1+9)/9 = 32/9 .
-7+30в+14в+3 = -4+44в = -4+44 (-1/4 ) = -4-11=-15
1) (x+7)(x+2)=x^2+2x+7x+14=x^2+9x+14.
2)
3) (x-3)(x+9)=x^2+9x-3x-27=x^2+6x-27
4)
(8 7/12 - 2 17/36)*2.7-4 1/3 : 0.65=289/39
8 7/12 - 2 17/36 = 103/12-89/36=309/36-89/36=220/36
2.7=2 7/10=27/10
220/36*27/10=66/4=33/3
4 1/3 : 0.65=7/3 : 65/100=7/3*100/65=700/195=140/39
33/3-140/39=429/39-140/39=289/39