Answer:
3rd option
Step-by-step explanation:
Given
y +
= 6 ( multiply through by 4 to clear the fraction
4y + 3 = 24 ( subtract 3 from both sides )
4y = 21 ( divide both sides by 4 )
y =
= 5 
Answer:

Step-by-step explanation:




.....<em>final answer.</em>
Answer:
9x-14
Step-by-step explanation:
7 times 2 is 14, and 5x plus 4x is 9x so it is 9x-14
Answer:
x = 1
y = -1
z = 2
Step-by-step explanation:
You have the following system of equations:

First, you can subtract euqation (3) to equation (1):
x + 2y - z = -3
<u>-x +y -z = - 4 </u>
0 3y -2z = -7 (4)
Next, you can multiply equation (3) by 2 and subtract it to equation (2):
2[ x -y + z = 4]
<u> -2x +y -z = -5</u>
0 -y + z= 3 (5)
You multiply equation (5) by 2 and sum (5) with (4):
2[ -y + z = 3]
<u> 3y -2z= -7</u>
y + 0 = -1
Then y = -1
Next, you replace y=-1 in (5) to obtain z:
-(-1) + z = 3
z = 2
Finally, you can replace z and y in the equation (3) to obtain x:
x - (-1) + (2) = 4
x = 1
The summation symbol means we use the variable i in the equation from the given range. In this case, we are given with the equation 3 i - 15 and i ranges from 2 to 7. The summation using simply the calculator is equal to -9. The answer to this problem is -9.