Now, for n = - 2
5n² + 5n-2 = 8 and n³ = (- 2)³ = (- 2) x (- 2) x (- 2) = - 8
Combining,
n³ + 5n² + 5n - 2 = - 8 + 8 = o.

Value of a² + b² + 3ab at a = 1 and b = - 2
= (1)² + (-2)² + 3(1)(- 2)
=1+4-6
=5-6
= -1

- 3x³y² +2x²y³
             -3x²y³-5y^{4
________________}
- 3x³y² +x²y³-5y^{4
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Sum =- 3x³y² +x²y³-5y⁴
Now,                 x⁴ +x³y² + x²y³ + y⁴
                            - 3x³y² - x²y³ - 5y⁴
                            (+)     (+)        (+)       
                       __________________ 
Difference =     x⁴ +4x³y²+2x²y³+ 6y⁴
                       ___________________

mn + 5-2
mn + 3
Adding, 2mn + 8-2 = 2mn + 6

2x²+ x + 7 + 4(x - 5) = 2x²+ x + 7 + 4x - 20
= 2x²+ x + 4x + 7-20
= 2x²+ 5x-13;
If x = 3, given expression
= 2(3)²+ 5(3)- 13
= 18 + 15 - 13 = 20

The simplified expression is 6 - 8b and its required value is 22.

Since, Ravi's age is not given.
\(\therefore\) Let Ravi's age be x years. Then, his father's age is 4 x yr. To find Ravi's grandfather's age, we have to take sum of Raci's age(x) and his father's age (4x) and to the sum add 15, i.e. is we have to take the sum of x, 4x and 15.

a² + b² + 2ab

The like terms are 7xy²z,- 15xy²z, 10zxy²,13y²xz 

In the expression -4x + 5, terms are -4x, 5 and factors of -4x are -4, x and factor of 5 is 5.

We have, y -y³
Here, terms are y and - y³ . Factor of y is y and factors of -y³ is -1, y, y, Y Now, to show terms and factors, tree diagram is given below

We know that, the product of y and z is yz. Then, subtract yz from 10, we get 10 - yz.

We know that, the product of numbers m and n is mn and its three times is 3mn. Then, add 5 in this product, we get 3mn + 5.

In 4x² - 5x, first obtain x² by multiplying the variable x by itself and then multiply x² by 4 to get 4x². From 4x², subtract the product of 5 and x, to get the expression 4x² - 5x.

In x² y, first obtain x² by multiplying the variable x by itself and then multiply x² by y to get the expression x²y