Surface area - multi step

£208

Step-by-step explanation:

Given:

Height of solid box (h) = 20 cm

Width (w) = 80 cm

Length (l) = 10 cm

Cost of paint = £0.04 per cm²

Required:

Cost of painting the box

Solution:

✔️First, find the surface area of the box

Surface area = 2(l*w + l*h + w*h)

S.A = 2(10*80 + 10*20 + 80*20)

S.A = 2(800 + 200 + 1,600)

S.A = 2(2,600)

S.A = 5,200 cm²

✔️Find the cost of painting 5,200 cm² surface area of the box.

Cost of pianting 1 cm² = £0.04

Cost of painting 5,200 cm² = 5,200 × 0.04

Cost of painting the box = £208

x = -4

step-by-step explanation:

- 20 - 4(x + 3) = 4x

=> -20 - 4x - 12 = 4x

=> - 32 -4x = 4x

=> -32 = 4x + 4x

=> - 32 = 8x

=> -32/8 = x

=> -4 = x