Answer:
Step-by-step explanation:
we have a 51 in sandwich
let a piece be x
we have x= shorter piece
another piece is x+6
another piece (x+6)-9=x-3
x+x+6+x-3=51
3x=51-3
3x=48
x=48/3=16
x=16, longer piece is 16+6=22, shorter piece =10
Answer:
-1 - 4 i
Step-by-step explanation:
5 - (2 * i) - (2 * (3 + i)) =
-1 - 4 i
Added instead of distributing or multiplying
Answer:
11. 78
12. 4x² - 3x - 1
Step-by-step explanation:
11. Sum of n whole numbers = ½(n² + n)
Multiply
½*n² + ½*n
= n²/2 + n/2
To find the sum of the first 12 whole number, substitute 12 for n into the equation.
= 12²/2 + 12/2
= 144/2 + 12/2
= 72 + 6
= 78
12. Area of trapezoid = ½(a + b)*h
Where,
a = 5x - 4
b = 3x + 2
h = x + 1
Area = ½(5x - 4 + 3x + 2)*(x + 1)
Area = ½(8x - 2)*(x + 1)
Area = ½[8x(x + 1) -2(x + 1)]
= ½[8x² + 8x - 2x - 2]
Add like terms
= ½(8x² - 6x - 2)
= ½(8x²) - ½(6x) - ½(2)
= 4x² - 3x - 1