Question

Help me pls and thank you :)

Answer 1

350

Explanation:

∑ (xy) means the sum of the products of x and y , that is

∑ (xy)

= (7 × 2) + (2 × 5) + (5 × 7) + (9 × 4) + (6 × 2) + (10 × 9) + (9 × 9) + (8 × 4) + (4 × 10)

= 14 + 10 + 35 + 36 + 12 + 90 + 81 + 32 + 40

= 350