text: These two problems are examples of simultaneous linear equations in two unknowns.\n\nsolution for prob. 1:\nx + y = -8 ---> eq.1\n-3x + 2y = 9 ---> eq. 2\n\nsolve for x in eq.1 \nx = -8 - y ---> eq. 3 \n\nsubstiture eq. 3 in eq. 2\n-3(-8 - y) + 2y = 9\n24 + 3y + 2y = 9\n24 + 5y = 9\nsolve for y\n5y = 9 - 24\n5y = -15\nthen y = -3 substitute this back in eq. 3 to solve for x: x = -8 - (-3)\n         x = -8 + 3\n         x = - 5\ntherefore the missing values for x and y are -5 and -3 respectively\n\nsolution for problem # 2:\ny = x + 5 eq. 1\nx + y = 9 eq. 2\nsubtitute eq. 1 in eq. 2\nx + (x+5) = 9\n2x + 5 = 9\n2x = 9 -5\n2x = 4\nx = 2 substitute this back in eq. 1\ny = 2 + 5\ny = 7\nthe values for x and y are 2 and 7 respectively\n\nhope this helps :-)