In which ones do i use elimination or substitution?

Find the area of a trapezoid with bases 14 cm and 18 cm and height 10 cm. 160 cm2 140 cm2 180 cm2 126 cm2

Our goal is to collect email addresses from 60% of customers who purchase a product." so that means if i talk to 95 customers, i need to persuade to provide an email address?

Graph the linear function using the slooe and y intercept