Advanced Math practice question

Answer: 3

Write 2^(x+3) as 8 · 2^x. Then 8 · 2^x − 2^x = 7 · 2^x = 56, so 2^x = 8 = 2³ and x = 3.

Common wrong answers

If you answered 4

4 comes from 2^x = 16, dividing 56 by 3.5 or by a slip in 8 − 1 = 7.

If you answered 7

7 is the factor 8 − 1, not x.

If you answered 8

8 is the value of 2^x, not x.

More Advanced Math questions

• Very hard
  The function f(x) = x² + 6x + 5 is rewritten in the form f(x) = (x + a)² + b. What is the value of b?
• Very hard
  What is the solution to the equation 6/(x − 2) = 3?
• Very hard
  The polynomial p(x) = x³ − 4x has how many distinct real zeros?
• Very hard
  The polynomial p is defined by p(x) = x³ + ax² + bx − 12, where a and b are constants. If x − 2 is a factor of…
• Very hard
  The function f, defined by f(x) = 3000(1.331)^(x/12), gives the value, in dollars, of an investment x months a…
• Very hard
  In the xy-plane, the parabola y = x² − 4x + 7 and the line y = mx − 2, where m is a constant, intersect at exa…