w-(-3)=7
Pretend that there is a -1 in front of the bracket
w-1(-3)=7
Mutiply the bracket by -1
(-1)(-3)=3
w+3=7
Move +3 to the other side. Sign changes from +3 to -3.
w+3-3=7-3
w=4
Answer: w=4
2/15
90 ÷ 6 = 15
Theoretical probability would be 15 due to the equation above
Total purchase she did : $20.90+$18.95=$39.85
7% tax means that we have to 7% or (7/100) extra
7% X 39.85= 2.79
total pay: 39.85+2.79=42.64
total cash: $50
what she gets back: 50-42.64=7.36