7. Given that log,4 = a and log:15 = b, find an expression for log3 20 in terms of a and b without using a calculator.b) y = log3(x + 2) +1 5\f2. An earthquake of 6.7 occurred off the coast of British Columbia. A few hours later, an aftershock occurred that was 150 times less intense as the original earthquake. What was the magnitude of the aftershock? Give your answer to one decimal place.3. An initial investment of $900 that is compounded quarterly grows into $1400 in 12 years. What was the interest rate to one decimal place? 4. A population of 1200 badgers grows by 6% every 8 years. How long does it take the population of badgers to grow to 2000? Round to the nearest year. 5. The intensity of light decreases by 4% for each meter that it descends below the surface of the water. At what depth is the intensity of light only 20% of that at the surface? Round to one decimal place4. Egg yolks have a pH of 6.4. What is the pH of egg whites if they are 63 times more alkaline