10x + 7y = –8
7x + 7y = –14

(2, - 4 )

Step-by-step explanation:

Given the 2 equations

10x + 7y = - 8 → (1)

7x + 7y = - 14 → (2)

Subtract (2) from (1) term by term to eliminate y

(10x - 7x) + (7y - 7y) = - 8 - (- 14) , that is

3x = 6 ( divide both sides by 3 )

x = 2

Substitute x = 2 into either of the 2 equations and solve for y

Substituting into (1)

10(2) + 7y = - 8

20 + 7y = - 8 ( subtract 20 from both sides )

7y = - 28 ( divide both sides by 7 )

y = - 4

solution to the system of equations is (2, - 4 )

this is answer of 144 cubic meters

the answer is b.

64

step-by-step explanation:

c=2πr=2·π·8≈64