Find the value of 2.7 ³ - 1.6 ³ - 1.1 ³ using a suitable identity.

14.256

See details below

Step-by-step explanation:

2.7 ³ - 1.6 ³ - 1.1 ³

= (2.7 ³  - 1.1 ³) - 1.6 ³   expand difference of two cubes

= (2.7 - 1.1)*(2.7^2 + 2.7*1.1 + 1.1^2) - 1.6 ³    

= 1.6*(2.7^2 + 2.7*1.1 + 1.1^2) - 1.6 ³    factor out 1.6

= 1.6*(2.7^2 - 1.6^2 + 2.7*1.1 + 1.1^2)    expand difference of two squares

= 1.6*( (2.7 - 1.6)*(2.7 + 1.6) + 2.7*1.1 + 1.1^2)

= 1.6*( 1.1*4.3 + 2.7*1.1 + 1.1^2)    factor out 1.1

= 1.6*1.1* ( 4.3 + 2.7 + 1.1)

= 1.6*1.1*8.1    rearrange

= 1.6 * 8.1 * 1.,1

= 16 * 0.81 * 1.1

= (4*0.9)^2 * 1.1

= 3.6^2 * 1.1  

= 12.96 * 1.1              36*36=1296

= 14.256    

(to multiply by 1.1, mentally start from the right, add the left digit, carry if necessary)

answer:  

step-by-step explanation:

here x represents the height of the pole,

and, the height of the shadow of the pole is 12 feet.

also, the angle of elevation from the top of the pole is 40°,

therefore,

by the low of sine,

which is the required equation for finding the value of x,

< coa = 150 ( given)

as ba and bc are tangents

so oc and oa is perpendicular to cb and ab respectively because in circle normal passes through centre

so in quadrilateral oabc

< coa + < oab + < ocb + < abc = 360

150 +90+90 + < abc = 360

330 + < abc = 360

< abc = 360 -330 = 30

so < abc = 30

⭐dhruv⭐