Simplifying
4x3 + -81x = 0
Reorder the terms:
-81x + 4x3 = 0
Solving
-81x + 4x3 = 0
Solving for variable 'x'.
Factor out the Greatest Common Factor (GCF), 'x'.
x(-81 + 4x2) = 0
Factor a difference between two squares.
x((9 + 2x)(-9 + 2x)) = 0
Subproblem 1
Set the factor 'x' equal to zero and attempt to solve:
Simplifying
x = 0
Solving
x = 0
Move all terms containing x to the left, all other terms to the right.
Simplifying
x = 0
Subproblem 2
Set the factor '(9 + 2x)' equal to zero and attempt to solve:
Simplifying
9 + 2x = 0
Solving
9 + 2x = 0
Move all terms containing x to the left, all other terms to the right.
Add '-9' to each side of the equation.
9 + -9 + 2x = 0 + -9
Combine like terms: 9 + -9 = 0
0 + 2x = 0 + -9
2x = 0 + -9
Combine like terms: 0 + -9 = -9
2x = -9
Divide each side by '2'.
x = -4.5
Simplifying
x = -4.5
Subproblem 3
Set the factor '(-9 + 2x)' equal to zero and attempt to solve:
Simplifying
-9 + 2x = 0
Solving
-9 + 2x = 0
Move all terms containing x to the left, all other terms to the right.
Add '9' to each side of the equation.
-9 + 9 + 2x = 0 + 9
Combine like terms: -9 + 9 = 0
0 + 2x = 0 + 9
2x = 0 + 9
Combine like terms: 0 + 9 = 9
2x = 9
Divide each side by '2'.
x = 4.5
Simplifying
x = 4.5
Solution
x = {0, -4.5, 4.5}
1. x = -0.2; y = -3.4
2. x = 3.75; y = -2.75
Объяснение:
1. 2x - y = 3, y = 2x - 3
3x + y = 3x + 2x - 3 = 5x - 3 = -4, 5x = -1, x = -0.2, y = 2 * -0.2 - 3 = -3.4
2. x - 7y = 23, x = 23 + 7y
3x - y = 3(23+7y) - y = 69+21y - y = 69 + 20y = 14, 20y = -55, y = -2.75, x=23+7*-2.75=3.75