Can someone show me the workings out for each of these three questions

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10

An energy drink company claims that its product increases students' memory levels. to support its claims, the company issues advertisements claiming that 8 out of 10 people (chosen randomly from across the country) who tried their product reported improved memory. the missing component in this study is a .

Iwill give you ! what is the measure of ∠v ?