Need Help! 50 points!!

see below

Step-by-step explanation:

eq.1      2a   - b + 2c = -8

eq.2            5b  - 3c =  21

eq.3     -7a        -10c = -2

3 equations, 3 unknown.

first step is to eliminate b using eq1 and eq2

2a   - b + 2c = -8 (5)

      5b  - 3c =  21

10a - 5b + 10c = -40

        5b -  3c =  21

10a        + 7c = -21 eq. A

lets solve a using eq. A

10a + 7c = -21

a = (-7c - 21) / 10

now substitute a into eq.3

-7a        -10c = -2

-7(-7c - 21) -10c = -2 distribute

        10

4.9c + 14.7 - 10c = -2  add similar terms

-5.1c = -2 - 14.7  simplify

c = -16.7 / -5.1

c  ≈ 3

solve b using eq. 2 and substitute c.

5b  - 3c =  21

5b = 21 + 3c

5b = 21 + 3(3.2)

b = 30.825 / 5

b ≈ 6

solve a using eq. A

10a + 7c = -21

10a + 7(3.2) = -21

10a = -21 - 22.4

a = -43.4 / 10

a ≈ -4

the height of the surface increases from the center out to the sides of the road.

step-by-step explanation:

as we move out we move away from the x-axis.

and as mentioned in the problem statement that height of a road increases when we move away from the center x.

hence proved that 3rd option

the height of the surface increases from the center out to the sides of the road.

is the correct option.

answer: 60%

explanation:

÷

= 60%