MKL = 83, JKL = 127, JKM = 9x - 10 <em>given</em>
JKL + MKL = JKM <em>angle addition postulate</em>
127 + 83 = 9x - 10 <em>substitution</em>
210 = 9x - 10 <em>simplify (add like terms)</em>
220 = 9x <em>addition property of equality</em>
= x