Question

Example

Cameron buys a stapler. Then he buys 5 notebooks that cost $1.50 each. He
spends $13.50 in all. Use the equation d + 5(1.50) = 13.50 to find the
number of dollars, d, that Cameron spends on the stapler.
d+5(1.50) - 13.50
Multiply 1.50 by 5
d+7.50 = 13.50
Subtract 7.50 from both sides. d + 7.50 -7.50 - 13.50 -7.50
Cameron spends $6 on the stapler.
In the Example, why is 7.50 subtracted from both sides of the equation?

Why can you replace the expression d + 7.50 -7.50 with just the variable d in the
last step of solving the equation?
Your answer Please help me out I’m struggling with this

Answer 1

because 5(1.50) is equal to 7.50 and they subtract it from both sides so that they can be left with the stapler and how much was spent on the stapler. You can replace d+7.50-7.50 with d because 7.50-7.50 is equal to zero