Answer:
8
Step-by-step explanation:
average is calculated as
average = 
= 13 ( multiply both sides by 2 )
sum of 2 eldest = 26
Then for the 4 children
average = 
= 
= 8
5x - 2y + 1z = 8 ⇒ 5x - 2y + 1z = 8
-9x + 2y + 2z = 5 ⇒ -9x + 2y + 2z = 5
-9x - 2y - 5z = 4 -4x + 3z = 13
5x - 2y + 1z = 8
-9x + 2y + 2z = 5 ⇒ -9x + 2y + 2z = 5
-9z - 2y - 5z = 4 ⇒ -9x - 2y - 5z = 4
-18x - 3z = 9
-4x + 3z = 13
-18x - 3z = 9
-22x = 22
-22 -22
x = -1
-18x - 3z = 9
-18(-1) - 3z = 9
18 - 3z = 9
- 18 - 18
-3z = -9
-3 -3
z = 3
5x - 2y + z = 8
5(-1) - 2y + 3 = 8
-5 - 2y + 3 = 8
-2y - 5 + 3 = 8
-2y - 2 = 8
+ 2 + 2
-2y = 10
-2 -2
y = -5
(x, y, z) = (-1, -5, 3)
Answer: She is incorrect because 0 + 0 = <u>0</u>
Answer:
x^2+x+1
Step-by-step explanation:
(3x^2+4x−1)+(−2x^2−3x+2)
Combine like terms
3x^2-2x^2+4x-3x-1+2
x^2+x+1
Hey there! :)
Answer:
y = 11.
Step-by-step explanation:
Set both of the equations equal:
5x - 9 = x² - 3x + 7
Rearrange the equation:
0 = x² - 3x - 5x + 9 + 7
Combine like terms:
0 = x² - 8x + 16
Factor:
0 = (x -4)²
Solve for x:
0 = x - 4
x = 4.
Plug this into an equation to solve for 'y':
y = 5(4) - 9
y = 20 - 9
y = 11.
