Please help on this question

18a

step-by-step explanation:

simply because it is. it's the highest common factor

i think it's ф or x=6,-6

step-by-step explanation:

-x^2=-36

x^2=-36

ф

or

if you mean by : -(x^2)=-36

it'll be: x^2=36

x=6,x=-6

hope it'll ! have a good day!

you for asking!

point a is the center of the circle that passes through points e, f, and g and the center of the circle that passes through points x, y, and z.