Find the area of the following polygons:

84 m²

Step-by-step explanation:

The polygon is composed of a rectangle and a triangle.

area of rectangle = 12 × 4 = 48 m²

area of triangle = × 12 × (10 - 4) = 6 ×6 = 36 m²

Total area = 48 + 36 = 84 m²

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15