How to solve the equation 2x + 5 = 21

How to solve the equation 2x + 5 = 21

Because the solution of 3x + 5 = 0 is minus 5 / 3
Substituting: 2x plus 1 / 2 = 1 / 2 minus?
10 out of 3 + 1 out of 2 = 5 out of 6 -?
So the constant is 12 out of 6

Solution equation: (x ^ 2-2x) ^ 2 = 2x ^ 2-4x + 3

(x^2-2x)^2=2x^2-4x+3
[x(x-2)]^2=2x(x-2)+3
Let X-2 = a
(xa)^2-2xa-3=0
(xa+1)(xa-3)=0
Xa = - 1 or 3
Because a = X-2
So x (X-2) = - 1, the solution is x = 1
X (X-2) = 3, the solution is x = 3 or - 1
X = 1 or - 1 or 3

Solving equation 2 (x-1) + X (x-1) = 0 4x (2x-1) = 3 (2x-1)

1. The expansion equation is: 2x-2 + X & sup2; - 1 = 0
x²+2x-3=0
(x+3）*（x-1)=0
X = 1 or x = - 3
(4x-3) * (2x-1) = 0
X = 1 / 2 or x = 3 / 4

Solving the equation x ^ 2-4x-9 = 2x-11

x^2-4x-9=2x-11
x^2-6x-9=-11
x^2-6x+2=0
From the formula x = {- (- 6) ± √ ￣ [(- 6) ^ 2-4 * 2]} / 2
x=3)±√￣7