Question

What is -7 (3a-1)=91 what does a equal

Answer 1

Answer:

a = -4

Step-by-step explanation:

Solve for a:

-7 (3 a - 1) = 91

Divide both sides of -7 (3 a - 1) = 91 by -7:

(-7 (3 a - 1))/(-7) = 91/(-7)

(-7)/(-7) = 1:

3 a - 1 = 91/(-7)

The gcd of 91 and -7 is 7, so 91/(-7) = (7×13)/(7 (-1)) = 7/7×13/(-1) = 13/(-1):

3 a - 1 = 13/(-1)

Multiply numerator and denominator of 13/(-1) by -1:

3 a - 1 = -13

Add 1 to both sides:

3 a + (1 - 1) = 1 - 13

1 - 1 = 0:

3 a = 1 - 13

1 - 13 = -12:

3 a = -12

Divide both sides of 3 a = -12 by 3:

(3 a)/3 = (-12)/3

3/3 = 1:

a = (-12)/3

The gcd of -12 and 3 is 3, so (-12)/3 = (3 (-4))/(3×1) = 3/3×-4 = -4:

Answer: a = -4

Answer 2

Answer:

a = -4

Step-by-step explanation:

Step 1: Write out equation

-7(3a - 1) = 91

Step 2: Distribute -7

-21a + 7 = 91

Step 3: Subtract 7 on both sides

-21a = 84

Step 4: Divide both sides by -21

a = -4