Envision Math 2.0: Grade 8, Volume 1
EM
Envision Math 2.0: Grade 8, Volume 1 View details
4. Equations with No Solutions or Infinitely Many Solutions
Continue to next subchapter

Exercise 25 Page 110

Solve the equation and try not to use subtraction.

&âś“ The operations that can be used to solve the & equation are addition and multiplication. &* The operations that can be used to solve the & equation are multiplication and division. &* The equation has infinitely many solutions. &* The equation has a solution ofx=53. &âś“ The equation has no solutions.

Practice makes perfect
We are asked to select all statements that apply to the equation 10x+45x-13=5(11x+6). & The operations that can be used to solve the & equation are addition and multiplication. & The operations that can be used to solve the & equation are multiplication and division. & The equation has infinitely many solutions. & The equation has a solution ofx=53. & The equation has no solutions. First, let's try to solve the given equation.
10x+45x-13=11(5x+6)
10x+45x-13=11(5x)+11(6)
10x+45x-13=55x+66
55x-13=55x+66

Notice that we can now stop solving the equation because any number (for example, 55x) cannot be equal to the same number (55x) after adding 66. 55x-13≠ 55x+66 Therefore, the given equation has no solutions. We can already select one of the options from the list. & The operations that can be used to solve the & equation are addition and multiplication. & The operations that can be used to solve the & equation are multiplication and division. & The equation has infinitely many solutions. & The equation has a solution ofx=53. &✓ The equation has no solutions. Since the equation has no solutions, it does not have a solution of x=53. Also, the equation cannot have infinitely many solutions if it does not even have one solution. & The operations that can be used to solve the & equation are addition and multiplication. & The operations that can be used to solve the & equation are multiplication and division. &* The equation has infinitely many solutions. &* The equation has a solution ofx=53. &✓ The equation has no solutions. To solve the equation, we used only addition and multiplication. Therefore, we will select the first option. &✓ The operations that can be used to solve the & equation are addition and multiplication. & The operations that can be used to solve the & equation are multiplication and division. &* The equation has infinitely many solutions. &* The equation has a solution ofx=53. &✓ The equation has no solutions. Finally, we will decide if we want to select the second option. In the last step of solving the equation we had to combine the x-terms on the left-hand side of the equation using addition. 10x+45x-13=55x+66 ⇕ 55x-13=55x+66 This was necessary to clearly see that the equation has no solutions. Therefore, this equation cannot be solved using only multiplication and division — we also need addition. Because of this, we will not select the second option. &✓ The operations that can be used to solve the & equation are addition and multiplication. &* The operations that can be used to solve the & equation are multiplication and division. &* The equation has infinitely many solutions. &* The equation has a solution ofx=53. &✓ The equation has no solutions.