Question

y⁴ -3x y³ + 7x² y² -2 x³y, para x= 1 e y= 2

Answer 1

16-3·1·8+7·1·4-2·1·2
16-24+28-4
16+4-4
16

Answer 2

 $y^{4}$ - 3xy³ + 7x²y² - 2x³y
$2^{4}$ - 3.1.2³ + 7.1².2² - 2.1³.2
16 - 24 + 28 - 4
20 - 4
16