Question 330965
multiplying 1st equation by -5 ___ -10r + 25s = 35


multiplying 2nd equation by 2 ___ 10r - 4s = 110


adding resulting equations (eliminating r) ___ 21s = 145 ___ s = 145/21


substituting ___ 2r - 5(145/21) = -7 ___ 42r - 725 = -147 ___ 42r = 578 ___ r = 289/21