Answer:
k = - 2
Step-by-step explanation:
( 2x - y )²
Formula : -
( a - b )² = a² + b² - 2ab
Here,
a = 2x
b = y
( 2x - y )²
= ( 2x )² + y² - 2 ( 2x ) ( y )
= 4x² + y² - 4xy
So,
( 2x - y )² = 4x² + y² - 4xy
( 2x + y )²
Formula : -
( a + b )² = a² + b² + 2ab
Here,
a = 2x
b = y
( 2x + y )²
= ( 2x )² + y² + 2 ( 2x ) ( y )
= 4x² + y² + 4xy
So,
( 2x + y )² = 4x² + y² + 4xy
( 2x - y )² - ( 2x + y )²
= 4x² + y² - 4xy - ( 4x² + y² + 4xy )
= 4x² + y² - 4xy - 4x² - y² - 4xy
= 4x² - 4x² + y² - y² - 4xy - 4xy
= 0 + 0 - 8xy
= - 8xy
( 2x - y )² - ( 2x + y )² = 4xyk
- 8xy = 4xyk
Divide 4xy on both sides,
- 8xy / 4xy = 4xyk / 4xy
- 2 = k
k = - 2
Therefore, the value of k is - 2.
Answer:
Step-by-step explanation:
If the area of trapezoid is 100 cm²what is the perimeter of the trapezoid?
Area of a trapezoid = 100cm
= 1/2(a + b) × h = 100cm²
Perimeter of a trapezoid = a + b + h
<h3>Given</h3>
z = 3
2y +z = 1
2x +3y +2z = 13
<h3>Find</h3>
x, y, z
<h3>Solution</h3>
... z = 3 is given
Substitute that into the second equation.
... 2y + 3 = 1
... 2y = -2 . . . . . subtract 3
... y = -1 . . . . . . . divide by the coefficient of y
Substitute these two solutions into the third equation.
... 2x +3(-1) +2(3) = 13
... 2x = 10 . . . . . . . . . . . . collect terms, subtract 3
... x = 5 . . . . . . . . . . . . . . divide by the coefficient of x
The variable values are: x = 5, y = -1, z = 3
Answer:
3 groups of -2
As the digit in the bracket is in negative form,
when we multiply positive times negative it will definitely be negative
Answer:
3000÷10=300
Step-by-step explanation:
3 litres is equal to 3000 millilitres so divide 3000 by 10 as there are 10 students.
