<span>x^2+8x-20=0
Factor the left side of the equation
</span><span><span>(x−2)</span><span>(x+10)</span></span>=<span>0
</span>
Set the factors to both equal the number 0
<span><span>x−2</span>=<span><span><span>0
and/or
</span>x</span>+10</span></span>=<span>0
</span>x = 2 and/or x = -10
Continental crust is 2.7-3.0
Oceanic crust is 3.0-3.3
Mantle is 3.3-5.7
Outer core is 9.9-12.2
Inner core is 12.6-13.0
C. formal regions are known as "formal" because of the characteristics known by the people who live there and/or visit there
