Step-by-step explanation:
me manda as respostas em português
Standard form is
ax+by=c
where a,b,c are integers
y+3=1/4x
timesboth sides by 4
4y+12=x
minus x both sides
-x+4y+12=0
minus 12 both sides
-x+4y=-12
(I like x to be positive so)
times both sides by -1
1x-4y=12
a=1
b=-4
c=12
Answer:
do its ??
Step-by-step explanation:
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
