Catch the Hidden Number
A number x is multiplied by 3, then 5 is added. The result is the same as 2 less than double the number.
Find x.
Word Problem
A bridge is built across a river. One quarter of the bridge is over the left bank of the river and one third of the bridge is over the right bank. The river is 120 m wide. How long is the bridge?
Multiply by 3, then add 5 gives: 3x + 5
ReplyDelete“2 less than double the number” means: 2x - 2
So: 3x + 5 = 2x - 2
Subtract 2x from both sides: x + 5 = -2
Subtract 5 from both sides: x = -7
Check:
3(-7) + 5 = -21 + 5 = -16
2(-7) - 2 = -14 - 2 = -16
Both match, so x = -7