Question

Please solve this question.(Quadratic equation)​

Answer 1

Answer:  28

Step-by-step explanation:

Let x represent the digit in the tens place and y represent the digit in the ones place.     xy → 10x + y

The square of the sum of the digits is 100.

EQ1: (x + y)² = 100       →    x + y = 10

2 is subtracted from 3 times the number is the digits reversed.

EQ2: 3(10x + y) - 2 = 10y + x    →   30x + 3y - 2 = 10y + x      →     29x - 7y = 2

Solve the system of equations using the Elimination method:

EQ1:      x +  y = 10    →  7(x + y = 10)     →      7x + 7y = 70

EQ2: 29x - 7y = 2     →  1(29x - 7y = 2  →   29x - 7y =  2    

                                                                    36x        = 72

                                                                 ÷36         ÷36  

                                                                            x = 2

Substitute x = 2 into either of the equations to solve for y.:

EQ1: x + y = 10

       2 + y = 10

            y = 8

The digit is: 28