Skip to main contentSkip to solution

The equation 2xx2=02^x - x^2 = 0 has

Solution

Correct Option: 4

We need to find how many values of xx satisfy: 2x=x22^x = x^2

In other words, where does the exponential function 2x2^x (red line) meet the parabola x2x^2 (blue line)?

Solution figure for IPMAT Indore 2026 MCQ question 5 (Algebra)

Let's plug in simple integer values and compare 2x2^x with x2x^2:

xx2x2^xx2x^22xx22^x - x^2
1-10.50.5110.5-0.5
001100+1+1
112211+1+1
22444400
3388991-1
441616161600
5532322525+7+7

So we already found two solutions: x=2x = 2 and x=4x = 4.


Now let's check for negative values of xx.

For very negative xx (say x=10x = -10), 2x2^x becomes tiny (close to 00), but x2x^2 becomes huge (100100). So x2>2xx^2 > 2^x.

At x=0x = 0: 2x=1>0=x22^x = 1 > 0 = x^2, so 2x>x22^x > x^2.

Since x2x^2 is above 2x2^x for very negative xx, but 2x2^x is above x2x^2 at x=0x = 0, the two curves must cross somewhere in between. This is guaranteed by the Intermediate Value Theorem — if one function overtakes the other, they must have been equal at some point.

This gives us a third solution in the negative region (approximately x0.77x \approx -0.77).


For x>4x > 4: 2x2^x grows exponentially while x2x^2 grows only as a polynomial, so 2x2^x stays above x2x^2 forever — no more crossings.

For x<0.77x < -0.77 going further left: x2x^2 keeps growing while 2x2^x keeps shrinking toward 00 — no more crossings.


The equation 2xx2=02^x - x^2 = 0 has 33 real solutions:

x=2,x=4,andx0.77x = 2, \quad x = 4, \quad \text{and} \quad x \approx -0.77

Keyboard Shortcuts

  • Left arrow: Previous question
  • Right arrow: Next question
  • S key: Jump to solution
  • Q key: Jump to question