32% of 1600 = 512
Use this fact to work out:
64% of 1600
96% of 1600
132% of 1600
232% of 1600.

Step-by-step explanation:

64% of 1600

  64% of 1600 = 2 × (32% of 1600) = 2×512

  64% of 1600 = 1024

96% of 1600

  96% of 1600 = 3 × (32% of 1600) = 3×512

  96% of 1600 = 1536

132% of 1600

  132% of 1600 = (100% of 1600) + (32% of 1600) = 1600 + 512

  132% of 1600 = 2112

232% of 1600

  232% of 1600 = (100% of 1600) + (132% of 1600) = 1600 +2112

  232% of 1600 = 3712

4

step-by-step explanation:

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