For all values of x, f(x)=2x+1 and g(x)=x^2. Solve fg(x)=gf(x). (Mathwatch)

it has to have an angle of 90 degrees

we can set up an equation, then solve for x.

will : -   18x + 483

tom : -   21x + 462

now, we combine these to get this :   18x + 483 = 21x + 462

we must solve for x now.

do the inverse operation ( get x on one side of the equation )

18x + 483 = 21x + 462

-18x           -18x

483 = 3x + 462

subtract 462 from both sides.

483 = 3x + 462

-462         - 462

21 = 3x

divide 3 form both sides.

21/3 = 3x/3

21/3 = x

x= 7