can someone answer these 2 questions and show the working out?

Adecibel is a logarithmic unit that can be used to measure the intensity of a sound. the function y = 10logx gives the intensity of a sound in decibels, where x is the ratio of the intensity of the sound to a reference intensity. the reference intensity is generally set at the threshold of hearing. use the graphing utility to graph the decibel function.a whisper has a sound intensity of 30 decibels. use your graph to you complete the following statement. the sound intensity of a whisper is times the reference intensity.

What number is 7 units left of -15?

The ratio of the perimeters of two similar triangles is 4: 3. what are the areas of these triangles if the sum of their areas is 130cm2?