Question

3. Tell which number is prime: 18, 42, 68, 79.

4.Find the value of the expression 48 8 + 4 x 4.

5.Evaluate (c − b)2 + a2 for a = –5, b = –2, and c = –4.

Answer 1

3. All of those numbers are prime. A prime number is a whole number greater than 1 whose only factors are 1 and itself. A factor is a whole numbers that can be divided evenly into another number.

4. 97

4. 14

Answer 2

1) 79

2) 400

3) 29

Explanation:

1) To find : Tell which number is prime: 18, 42, 68, 79.

Solution :

A prime number is defined as number which is only divisible by 1 and itself.

As 18,42 and 68 were divisible by 2.

But 79 is not divisible by any number.

Which means 79 is the only prime number which is divisible by 1 and itself.

2) To find : The value of the expression
`48* 8+4* 4`

Solution :

The expression,

`48* 8+4* 4`

`=384+16`

`=400`

Therefore,
`48* 8+4* 4=400`

3) Evaluate :
`(c- b)^2 + a^2` for a=-5, b=-2 and c=-4

Solution :

The expression is
`(c- b)^2 + a^2`

Substitute the values, a=-5, b=-2 and c=-4

`(c- b)^2 + a^2=(-4-(-2))^2+(-5)^2`

`(c- b)^2 + a^2=(-4+2)^2+25`

`(c- b)^2 + a^2=(-2)^2+25`

`(c- b)^2 + a^2=4+25`

`(c- b)^2 + a^2=29`