Area and lenth formula with pie

(a) solve h+2/6 = h-3/4(b) solve the following simultaneous equations. 2x = y + 66x - 2y = 13x = ? y = ?

After the seventh month of a 12-month loan: the numerator is: {(n + 11) + (n + 10) + (n + 9) + (n + 8) + (n + 7) + (n + 6) + (n + 5)} = , and the denominator is: {(n) + (n + 1) + + (n + 11)} = . therefore, the fraction is numerator/denominator (to the nearest tenth) = %

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