How do I solve a system of equation? Can someone explain it to me?

For example:

x - y = 4

2x + y = 5

Mr. George divided his money in the ratio 2:6 between Evan and Ricky. Evan got the smaller amount of 420 dirhams. How much did Ricky receive?

The table shows the relationship "Dental Assistants make 19 dollars per hour." Hours (h) Dollars (d) 1 19 2 38 3 57 4 76 5 95 Which statements are correct? Check all that apply. The variable d is the independent variable.

Subtract the product of 5 and 8 from 50 written as a numerical expression

A seamstress need to cut 15-inch pieces of ribbon from a roll of ribbon that is 9 feet in length. what is the greatest number of 15-inch pieces the seamstress can cut from 5 of these rolls of ribbon?

Find the range and interquality for 5,9,6'8'7

How many semesters in 4 years of college?

if a supplement of an angle has a measure 78 less than the measure of the angle, what are the measures of the angles?

The difference between the square root of x and pi squared

F=9/5C+32 solve the equation

Radical 5 - 2x + 5 = 12