What is the value of x in the equation x - y = 30, when y= 15?

What signals you that factoring by grouping is the best method to use when factoring a problem?

Which equation represents the line that passes through the points and (4, 10) and (2, 7)? y = 3/2x - 11y = 3/2x +4y = - 3/2x + 19y = - 3/2x + 16

Julius sold five times as many computers as sam sold last year. in total, they sold 78 computers. how many computers did julius sell?