Brianna solved a two-step equation, but she made a mistake along the way.

Question

0.1x + 3 = 1.7
(-3) + 0.1x + 3 = 1.7 + (-3) Line 1
0.1x = -1.3 Line 2
(-0.1) + 0.1x = -1.3 + (-0.1) Line 3
x = -1.4 Line 4
What mistake did Brianna make?

Answer 1

0.1x + 3 = 1.7
subtract 3 from both sides
0.1x + 3 -3 = 1.7-3
.1x = -1.3
divide both sides by .1
.1x /.1 = -1.3/.1
x = -13

You establish where her error was.