I believe that number one is 4<span />
<span>6(-3r)=-39+3r
-18r = -39+3r
39 = 18r + 3r
39 = 21r
39/21 = r
13/7 = r
r = 13/7</span>
A line does not describe a slope.
Correct scientific notation has only one number to the left of the decimal point.
The correct one would be: 3.4 x 10(exponent 3)