10x squared minus 5x

Question

My daughter has a maths question to subtract the area of one rectangle .....one side is 3, the other is x + 1 giving an area of 3x + 3 from a larger rectangle...one side is 5(2x - 1) the other side is x giving an area of 10x - 5 times x which hopefully equals 10x sq - 5x??? How does she subtract 3x + 3 from 10x squared - 5x  ??

Answer 1

Yes, the area of the smaller rectangle is 3x+3, and of the larger one 10x²-5x.

So the difference is 10x²-5x-3x-3=10x²-8x-3. It doesn’t simplify further, unless and until x is given a numerical value, or the expression is given a numerical value from which x can be calculated.