Question

If five times a certain integer is subtracted from the square of the integer, the integer is 63, find the integer

Answer 1

Step-by-step explanation:

Let the number be X

Five times a number 5X

Twice the X^2 =2X^2

2X^2-5X =63

2X^2-5X -63=0

a=2 b= -5 c= -63

X =[ 5+ — (25 -4×2×-’63)] / 2×2 =[5+ —(529)^1/2] /4

[Note : (529)^1/2 =23]

X1=(5+23)/4 =7

X2 =(5 -23)/4 = -18/4 not integer

The number is 7

Verification

2X^2= 2×49=98

5×X =5×7=35

Diffrence is 98-35= 63