x^2 + x = x^2 + 4

subtract x^2 from both sides-

x^2 - x^2 + x = x^2 - x^2 + 4

0 + x = 0 + 4

x = 4

x^2 + x = x^2 + 4

subtract x^2 from both sides-

x^2 - x^2 + x = x^2 - x^2 + 4

0 + x = 0 + 4

x = 4

1gm = 0.001 kg

So,

400gm = 400×0.001

= 0.4 kg

Make proportion.

30/240 = x/100

240x = 3000

x = 3000/240

x = 12.5%

I hope it'll help.

To convert cm³ into cm² follow the example-

Ex: Convert 4³ into 4²

4³ = 64 and 4² = 16

(cm × cm × cm)/cm = cm²

similarly,

(4 × 4 × 4)/4 = 4×4 = 4² = 16

'of' represents multiplication,

so, 1/3 × 20000

we can write 20000 as-

20000/1

Now, simply multiply fractions,

1/3 × 20000/1 = 1×20000/3×1

= 20000/3

= 6666.6666 or 6666.7

the number is prime the number is less the 19 the sum of the digits of the number is greater than 7?

The number is 17.

17 is less than 19 and the sum of the digits of 17 is 1+7 = 8, which is greater than 7

The nearest two 1 decimal numbers of 6.42 are 6.4 and 6.3

To round off this observe the digit at hundredth place i.e., 2

2 is less than 5 so it round down to 6.4