so you have your two equations 3x+7=5x-23 and solve for x which is your "number" leaving the answer to be <u>x=15</u>
Answer:
Subtraction is the inverse (opposite operation) of addition
Step-by-step explanation:
А=2
b=-8
c=-90
D=b^2-4ac
D=64+720
D=784=28^2
X1,2=(-b-+D):2a
Х1,2=(8+-28):4
Х1=-5
Х2=9