Find the surface area of a tetrahedron whose vertices are at the points A( 1, 2, -1 ) , B( 2, 0, 1 ) , C( -1, 1, 2 ) and D( 3, 2, 4 ).

Beth took out a $20,000 loan for college she is borrowing money from two banks. bank a charges an interest rate of 8.5% bank b charges and interest rate of 10.5% after one year alice owes $1860 in interest how much money did she borrow from bank a

On a architect's drawing of a house, 1 inche representa 1.5

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)