Based on the data from three annual checkups, jon’s mean height is 62 in. at the first two checkups, jon’s height was 58 in. and 61 in. what was his height at the third checkup?
a.
70
c.
65
b.
67
d.
62

  b.  67

Step-by-step explanation:

In order for the average to be 62, the total of differences from 62 must be zero. The two given numbers have differences of -4 and -1, for a total of -5. In order for the total of differences to be zero, the third number must have a difference from 62 of +5. It must be 62+5 = 67.

Jon's height at his third checkup was 67 inches.

{x = -1/2 ,   y = -1

step-by-step explanation:

solve the following system:

{2 x + y = -2

{10 x - 3 y = -2

in the first equation, look to solve for y:

{2 x + y = -2

{10 x - 3 y = -2

subtract 2 x from both sides:

{y = -2 x - 2

{10 x - 3 y = -2

substitute y = -2 x - 2 into the second equation:

{y = -2 x - 2

{10 x - 3 (-2 x - 2) = -2

10 x - 3 (-2 x - 2) = (6 x + 6) + 10 x = 16 x + 6:

{y = -2 x - 2

{16 x + 6 = -2

in the second equation, look to solve for x:

{y = -2 x - 2

{16 x + 6 = -2

subtract 6 from both sides:

{y = -2 x - 2

{16 x = -8

divide both sides by 16:

{y = -2 x - 2

{x = -1/2

substitute x = -1/2 into the first equation:

{y = -1

{x = -1/2

collect results in alphabetical order:

answer:   {x = -1/2 ,   y = -1