Solve the system of equations.
3x – 2 = –18 + 5y
8y – 6 = 4x + 9y
y – 10 = 3x + 2z
a. (–1, –4, –8)
b. (–2, 11, 7)
c. (–2, 0, –11)
d. (–2, 2, –1)

option D

Step-by-step explanation:

3x – 2 = –18 + 5y      Equation 1

8y – 6 = 4x + 9y        Equation 2

y – 10 = 3x + 2z         Equation 3

Using Equation 1 we have:

3X=-18+5Y+2

3X=-16+5Y

  Equation 4

Using Equation 3 we have:

Y-10-3X=2Z

So  Equation 5

Using equation 2 and substituting equation 4 we have:

Using Equation 4 we have:

Using Equation 5 we have:

Finally:

X=-2

Y=2

Z=-1

if gloria has "carry over" minutes, (that is, any minutes paid for but not used in a month can be applied to her payment for minutes in the next month,) her total usage for the three months is: total minutes = 320 + 243 + 489 = 1052 minutes number of 200 minute blocks = 1052/200 = 5 r52 (that is 5 with a remainder of 52) rounding up the number of 200 minute blocks gives her usage for the three months as 6 blocks. the cost for six blocks is 6 x $25 = $150 she also has 200 - 52 or 148 carry over minutes if gloria pays each month and unused minutes are lost, applying the rounding up procedure to each month gives: first month usage of 320 minutes rounds up to 2 blocks of 200 minutes for a payment of 2 x $25 = $50 second month usage of 243 minutes rounds up to 2 blocks of 200 minutes for a payment of 2 x $25 = $50 third month usage of 489 minutes rounds up to 3 blocks of 200 minutes for a payment of 3 x $25 = $75 total payments for the three months are $50 + $50 + $75 = $175 get the plan with carry over minutes!