Add 7, .8,.6 Add 35.15,14.18,7.16 Add .8,5,.7

(a) 8.4

(b) 56.49

(c) 6.5

Step-by-step explanation:

Question 1:

7 + 0.8 + 0.6

7.8 + 0.6

8.4

Question 2:

35.15 + 14.18 + 7.16

49.33 + 7.16

56.49

Question 3:

0.8 + 5 + 0.7

5.8 + 0.7

6.5

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