Question

plz help me to solve
ch - polynomial
class 9​

Answer 1

Answer:

1. -1728+343+125= -1260

2. 21952-3375-2197 =15380

Answer 2

${ \huge{ \bold{ \underline{ \underline{ \orange{Question:-}}}}}}$

Without actually calculating the cubes,Find the value of each of the following :

(i) (-12)³ + (7)³ + (5)³

(ii) (28)³ + (-15)³ + (-13)³

_______________

${ \huge{ \bold{ \underline{ \underline{ \purple{Answer:-}}}}}}$

$\dashrightarrow\sf\bold{(i)\:{(-12)}^{3}+{(7)}^{3}+{(5)}^{3}}$

$\dashrightarrow\sf{{\cancel{(-12}}+{\cancel{12)}}}$

✒By Using : -

→ x³ + y³ + z³ - 3xyz

$\dashrightarrow\sf{{x}^{3}+{y}^{3}+z=3xyz}$

→ If (x + y + z) = 0

$\dashrightarrow\sf{{(-12)}^{3}+{(7)}^{3}+{(5)}^{3}=3(-12)\:(7)\:(5)}$

$\leadsto\sf{{ \large{ \boxed{ \bold{ \bold{ \red{-1260}}}}}}}$

______________________________

$\dashrightarrow\sf\bold{(ii)\:{(28)}^{3}{(-15)}^{3}{(-13)}^{3}}$

$\dashrightarrow\sf{{\cancel{(28}}-{\cancel{28)}}}$

✒Using : -

→ x³ + y³ + z³ - 3xyz

$\dashrightarrow\sf{{x}^{3}+{y}^{3}+{z}^{3}=3xyz}$

→ If (x + y + z) = 0

$\dashrightarrow\sf{{(28)}^{3}+{(-15)}^{3}+{(-13)}^{3}=3(28)\:(-15)\:(-13)}$

$\dashrightarrow\sf{3(28)\:(-15)\:(-13)}$

$\leadsto\sf{{ \large{ \boxed{ \bold{ \bold{ \green{16380}}}}}}}$