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 answer is:

the answer is:

to solve the problem, we need to remember the quotient of power property, it's defined by the following relation:

if we have a quotienf of powers that have the same base, we need to keep the same base and subtract the exponent of the denominator power to the exponent of the numerator power.

so, we are given the expression:

then, calculating we have:

hence, the answer is:

have a nice day!