4a^2-2b^2+40 a=2. b=7

-92

Step-by-step explanation:

4a^2-2b^2+40 a=2. b=7

Fill in variables

4(2)^2-2(7)^2+40      a=2. b=7

8^2 - 14^2 + 40

64 - 196 +40 = -92

1/800 is the right answer

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