Answer:
Step-by-step explanation:
Use notation x for the unknown variable:
Let the unknown number be x
Translate from words to math :
The sum of (add two things)
the cube of a number (x³) and (+) the product (·) of the number (x) and 7
is equal to (=) eight times(8·) the square of the number(x²)
Write the mathematical equation:
x³+(x·7) = 8x²
Solve the equation to find x:
x³+7x = 8x², subtract 8x² from both sides
x³- 8x²+7x = 0, factor x
x(x²-8x+7) = 0, factor the quadratic equation (what 2 numbers have the sum 8, and product 7... numbers 1 and 7)
x(x-1)(x-7) = 0, find the roots (the solutions)
x= 0, x= 1, x= 7
Solution:
The equation given by the word problem is x³+7x = 8x²
The unknown number x, could be 0, 1, or 7
