How do you solve x + 3 = 15?
Think about the equation in words and steps: Start with x Add 3 Get 15 Reverse the order of the steps and do the opposite: Start with 15 Subtract 3 (15 - 3 = 12) Get x (x = 12) In other words, use inverse operations to get the value of x. Since it is x + 3, subtract 3 from both sides to get x = 12.
Why does -4 + 12 = 8?
Think about the problem in terms of money. If you owe me $4 (-4) and then you pay me $12 (+12) to cover your debt, you will have paid me $8 (= 8) extra.
Adrian wants to save for a new gaming console. He has already saved $35 and plans to save $10 per week. Write an inequality to represent the minimum number of weeks he must save for the new console. Then, determine the minimum number of weeks he must save in order to have at least $150 for the new console.
You will need to write an equation to represent the situation. Begin with what Adrian has already saved, which is $35. Since this amount does not change, it will not get a variable. Then, Look at the amount that Adrian will save each week. This amount is affected by the number of weeks that Adrian has saved, so that will get a variable. Together, this information gives you the overall equation of: y $$\geq$$ 10x + 35 where y = amount saved and x = number of weeks To have at least $150, solve the equation 150 $$\geq$$ 10x + 35. Use inverse operations to isolate the y. When you do this, you will get y $$\geq$$ 11.5. Answer: Adrian must save for at least 12 weeks to have at least $150 for the new console.