Question 4 :
Is it TRUE or FALSE, substituting x = -3 in $x^2+5x+4x$ gives $(-3)^2+5(-3)+4 = 9+2+4=15$ ?

Question 30 :
Express the result in power notation with positive exponent. $2^{– 3} × (–7)^{– 3}$

Question 33 :
Express in standard form: Charge of an electron is 0.000,000,000,000,000,000,16 coulomb.

Question 35 :
The distance between earth and sun is 150 million kilometres which can be written in exponential form as _______.

Question 37 :
<img style='object-fit:contain' src='https://teachmint.storage.googleapis.com/question_assets/cbse_ncert/61b1ccd1f59b460d7261edf2.PNG' /> Refer to the above image. Neha needs to stretch some sticks to $25^2$ times their original lengths, but her (×25) machine is broken. Find a hook-up of two repeater machines that will do the same work as a $(×25^2)$ machine. To get started, think about the hookup you could use to replace the (×25) machine.

Question 38 :
Express in standard form: Thickness of a thick paper is 0.07 mm