Simplify. (a−b+c)−(c+b)

a -2b

Step-by-step explanation:

(a−b+c)−(c+b)

Distribute the minus sign

a-b+c  -c -b

Combine like terms

a -b -b +c-c

a -2b

a - 2b

Step-by-step explanation:

(a - b + c) - (c + b)

= a - b + c - c - b

= a - 2b

x = ±sqrt(10)

step-by-step explanation:

5 - 2x² = -15

subtract 5 from each side

5-5 - 2x² = -15-5

-2x^2   = -20

divide by -2 on each side

-2x^2   /-2= -20/-2

x^2 =10

take the square root on each side

sqrt(x^2 )=±sqrt(10)

x = ±sqrt(10)

check:

5 - 2x² = -15

+sqrt(10)

5 - 2(sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15

-sqrt(10)

5 - 2(-sqrt(10))² = -15

5 -2(10) = -15

5 -20 = -15

-15 = -15