Question

George and Bella are asked to solve −3x − 30 = 5x + 18. Identify where one of them made an error.

George

Bella
− 3x − 30 = 5x + 18
− 3x − 30 − 5x = 5x + 18 −5x
−8x − 30 = 18
− 8x − 30 + 30 = 18 + 30
−8x = 48
Negative 8x over negative 8 equals 48 over negative 8
x = − 6

− 3x − 30 = 5x + 18
−3x − 30 − 3x = 5x + 18 − 3x
− 30 = 2x + 18
−30 − 18 = 2x + 18 −18
− 48= 2x
Negative 48 over 2 equals 2x over 2
x=−24

Answer 1

for the second,
In the first step, instead of adding 3x for both sides, they subtract 3x instead.

Answer 2

Answer:

Bella made an error in step 2

Step-by-step explanation:

The given equation is:

-3x-30=5x+18

Rearranging the like terms, we get

⇒-3x-5x=18+30

⇒-8x=48

⇒x=-6

Thus, the correct value of x is -6.

Now, Bella made a mistake in her solution as:

-3x-30=5x+18

⇒−3x − 30 − 3x = 5x + 18 − 3x  (she should add 3x on both sides rather than subtracting)

⇒− 30 = 2x + 18

⇒−30 − 18 = 2x + 18 −18

⇒− 48= 2x

⇒x=-24