Which expression is the simplest form

What is r i 4.5+10r=-6.5 with work pls

Write the percent as a fraction or mixed number in simplest form. 0.8%

Grandpa ernie is shrinking! over the past 4 years his height decreased by a total of 2.4 cm.it decreased by the same amount each year. what was the change in grandpa ernie's height each year