Hey Oldspice1212.
Please state the problem precisely: I have absolutely no idea what you are trying to actually calculate since you just give an answer without a question.
Given two vectors Vector A = 4.00i+7.00j and Vector B = 5.00i-2.00j , find the vector product A*B (expressed in unit vectors).
Express your answers in i,j,k.
I got 20.0i+14.0j+0k
What is magnitude of the vector product?
Either 280 or 0
Please check it.
It looks like you have been trying to take the dot product, not the vector product, or cross product.
The dot product results in a scalar, not a vector:
A dot B = 4*5 + 7*(-2) = 20 - 14 = 6
What method have you learned for calculating the cross product? Keep in mind the answer should be a vector that's perpendicular to both A and B.