Answer:
D
Step-by-step explanation:
It's the only equation that gets y correct in every one.
Step-by-step explanation:
- 3x+5y=7b equation 1
- 2x+4y=1
2x=-4y+1
- x=(-4y+1)/2
- x=(-4y+1)/2 in equation 1
3×(-4y+1)/2+5y=7b
(-12y+3)/2+5y=7b
(-12y+3+10y)/2=7b
(-12y+3)/2=7b
-12y+3=14b
-12y=14b-3
- y=3-14b/12
- y=3-14b/12 in x=(-4y+1)/2
x=(-4×{3-14b/12}+1)/2
x=(-3+14b)/3+1/2
x=14b/3×1/2
Answer:
The roots are;
x = (2 + i)/5 or (2-i)/5
where the term i is the complex number representing the square root of -1
Step-by-step explanation:
Here, we want to use the completing the square method to solve the quadratic equation;
f(x) = -5x^2 + 4x -1
Set the function to zero
0 = -5x^2 + 4x - 1
So;
-5x^2 + 4x = 1
divide through by the coefficient of x which is -5
x^2 - 4/5x = -1/5
We now take half of the coefficient of x and square it
= -2/5^2 = 4/25
add it to both sides
x^2 - 4x/5 + 4/25= -1/5 + 4/25
(x- 2/5)^2 = -1/5 + 4/25
(x - 2/5)^2 = -1/25
Take the square root of both sides
x - 2/5 = √( -1/25
x - 2/5 = +i/5 or -i/5
x = 2/5 + i/5 or 2/5 - i/5
