Answer :
Elena is wrong, because the two sides of equation are not equal for all values of x
Step-by-step explanation:
An equation of x is true for all values of x when the left hand side
is equal to the right hand side
To prove that an equation is true for all values of x do that
- Simplify the left hand side and the right hand side
- Solve the equation to find x, you will find the x in the left hand side is equal to x in the right hand side, so they canceled each other, and the numerical terms in the two sides equal each other, that means the equation is true for any values of x
Lets check that with given equation 5(x + 2) = 5x + 10
∵ 5(x + 2) = 5x + 10
- Simplify the left hand side
∵ 5(x) + 5(2) = 5x + 10
∴ 5x + 10 = 5x + 10
- Subtract 5x from both sides
∴ 10 = 10
∵ L.H.S = R.H.S
∴ The equation is true for all values of x
Lets do that with Elena's equation
∵ 20(x + 2) = 4(5x + 10) + 31
- Simplify the two sides of the equation
∵ 20(x) + 20(2) = 4(5x) + 4(10) + 31
∴ 20x + 40 = 20x + 40 + 31
- Add like terms in the right hand side
∴ 20x + 40 = 20x + 71
- Subtract 20x from both sides
∴ 40 = 71 ⇒ and that not true
∵ L.H.S ≠ R.H.S
∴ The equation is not true for all values of x
Elena is wrong, because the two sides of equation are not equal for all values of x
Learn more:
You can learn more about the equations in brainly.com/question/11306893
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Elena took the original equation, multiplied both sides of it by 4 and added 31 to both sides. Because she did the same thing to both sides of the equation, it is equal to the original equation and therefore is true for all values of `x`.