解?$:(2)$?已知?$ |m - 2| = 3,$?
根據(jù)絕對值的定義,絕對值是指一個數(shù)在數(shù)軸上所對應(yīng)點(diǎn)到原點(diǎn)的距離,
所以絕對值為?$3$?的數(shù)有兩個,分別為?$3$?和?$-3。$?
那么?$ m - 2 = 3 $?或者?$ m - 2 = -3。$?
當(dāng)?$ m - 2 = 3 $?時,通過等式兩邊同時加?$2,$?可得?$ m = 3 + 2 = 5。$?
當(dāng)?$ m - 2 = -3 $?時,同樣等式兩邊同時加?$2,$?可得?$ m = -3 + 2 = -1。$?
?$(3)a=3$?或?$a=-5$?