Simplify (7x10%) = (1 x 10%) and write the answer in scientific notation.
a. 7 x 10
b. 7
c. 7x10%
d. 7x 108

Parabolas y=−2x^2 and y=2x^2+k intersect at points a and b that are in the third and the fourth quadrants respectively. find k if length of the segment ab is 5.