While crossing a remote mountain pass, Emek and Tara found the safe trail blocked by a locked gate. A marker beside it explained that the gate code was the value of x satisfying 4(2x - 3) + 7 = 3(x + 5) + 20. Tara expanded both sides, obtaining 8x - 5 = 3x + 35. Emek suggested collecting the variable terms first. Subtracting 3x from both sides gave 5x - 5 = 35, and adding 5 gave 5x = 40. They found x = 8, but Tara insisted on checking before entering the code. In the original equation, the left side became 4(16 - 3) + 7 = 59, while the right side became 3(8 + 5) + 20 = 59. Since both sides matched, Emek entered 8. The gate unlocked, allowing them to continue along the protected trail before the mountain weather changed.

Challenges

Challenge 1 of 5

Challenges

Challenge 1 of 4
Hint
Distribute 4 to both terms inside the first parentheses and 3 to both terms inside the second parentheses.
Tara begins solving the gate equation 4(2x - 3) + 7 = 3(x + 5) + 20 by expanding both sides. Which equation is equivalent to the original equation after this step?
8x - 12 + 7 = 3x + 15 + 208x - 3 + 7 = 3x + 5 + 206x - 12 + 7 = 3x + 15 + 208x - 12 + 7 = 3x + 8 + 20
Correct. Distributing gives 8x - 12 + 7 on the left and 3x + 15 + 20 on the right.
Not quite. Apply the distributive property to every term inside each set of parentheses.
Next
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Hint
Expand both sides, combine like terms, and then isolate x.
A second trail marker uses the same type of code equation: 5(2x - 4) + 10 = 4(x + 5) + 6. What integer value of x unlocks this marker?
Correct. Solving the equation gives x = 6.
Check your distribution and combine like terms on each side before isolating x.
Next
🎉 Congrats! You got this question!
Hint
A solution to an equation must make the two sides equal when substituted into the original equation.
After Emek finds x = 8 for the original gate equation, why does substituting 8 into both sides and obtaining 59 = 59 confirm the solution?
It shows that 59 must be the gate code instead of 8.It shows that the left side is larger than the right side.It shows that x = 8 makes the original equation true because both sides have the same value.It shows that every value of x will make the equation true.
Correct. Substituting x = 8 makes both sides equal to 59, verifying the solution.
Not quite. Think about what must happen to the two sides of an equation when a correct solution is substituted.
Next
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🎉 Congrats! You finished this challenge set!
Dağ Geçidi Şifresi
TR
ARC_G10_OPS_02_STORY_01
Dağ Geçidi Şifresi
The Mountain Pass Code
EN
ARC_G10_OPS_02_STORY_01
The Mountain Pass Code