Nova, Luna, and Emek watched a satellite move toward its planned orbit. The navigation screen showed that its final position followed the equation 5x + 18 = 73, where x was the course adjustment in kilometers. Luna subtracted 18 from both sides and found 5x = 55. Emek divided by 5 and found x = 11 kilometers. Before changing the course, Nova checked the answer: 5(11) + 18 = 73. The value matched the required position, so they entered the 11-kilometer adjustment and guided the satellite safely into orbit.
Challenges
Challenge 1 of 5
Challenges
Challenge 1 of 4
Hint
Think about which operation will undo the addition of 18.
For the equation 5x + 18 = 73, which step correctly isolates the term 5x?
Add 18 to both sides to get 5x = 91.Divide both sides by 5 to get x + 18 = 14.6.Subtract 18 from both sides to get 5x = 55.Subtract 5 from both sides to get x + 18 = 68.Correct! Subtracting 18 from both sides leaves 5x = 55.
Try again. Use the opposite operation to remove the added 18 from both sides.
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Hint
First subtract 18 from both sides. Then divide by 4.
For a new satellite adjustment, the navigation screen shows 4x + 18 = 66, where x is the course adjustment in kilometers. What is the value of x?
Correct! The course adjustment is 12 kilometers.
Try again. Undo the addition first, then undo the multiplication.
Next🎉 Congrats! You got this question!
Hint
Replace x with 11 in the original equation and evaluate the left side.
Nova wants to check Emek's solution x = 11 for the original equation 5x + 18 = 73. Which calculation correctly checks the solution?
5(11) + 18 = 735 + 11 + 18 = 345(18) + 11 = 1015(11) - 18 = 37Correct! Substituting 11 gives 73, so the solution checks.
Try again. Substitute 11 for x without changing the operations in the original equation.
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