$\displaystyle\\
15(2a - 2) = 5(a^2 -1) \\ \\ 
30a - 30 = 5a^2-5\\\\
-5a^2 + 30a -30 + 5 =0\\\\
-5a^2 + 30a -25 =0 ~~~~~\Big| \times (-1) \\\\
5a^2 - 30a +25 = 0~~~~~\Big| : 5 \\\\
a^2 - 6a +5 = 0 \\ \\ 
a_{12}= \frac{-b\pm \sqrt{b^2-4ac}}{2a}= \frac{6\pm \sqrt{36-20}}{2}= \frac{6\pm \sqrt{16}}{2}=\frac{6\pm 4}{2}= \boxed{3\pm 2} \\ \\ 
a_1 = 3+ 2 = \boxed{5}\\\\
a_2 = 3-2 = \boxed{1}$

8 0

3 years ago

Read 2 more answers

What is the approximate volume of a cylinder with a height of 2 ft and a radius of 6 ft? Use 3.14 to approximate pi. Express you

marissa [1.9K]

The volume of a cylinder is Pi times the radius^2 times the height

Volume = Pi x 6^2 x 2
Volume = 226.2

6 0

3 years ago

-10x = -210 how would i find this answer?

jeka94

To find the answer to -10x=-210 you must divide -210 by -10

-210/-10= 21