Given two vectors a⃗ =4.00i^+7.00j^ and b⃗ =5.00i^−2.00j^ , find the vector product a⃗ ×b⃗ (expressed in unit vectors). what is the magnitude

We have the following vectors:
 a = 4.00i + 7.00j
 b = 5.00i-2.00j
 We make the vector product:
 a x b = (4 * (- 2)) k - (7 * 5) k = -8k -35k = -43k
 The magnitude of the vector is:
 la x bl = root ((- 43) ^ 2) = 43
 Answer:
 the vector product is:
 -43k
 the magnitude is:
 43