Question

solve for x
91= 6x + 1/2 × 9.8 × x²

Answer 1

Answer:

x = 3.73 or x = -4.96

Step-by-step explanation:

=> 91 = 6x+1/2*9.8*x²

=> 91 = 6x+4.9x²

=> 6x+4.9x²-91 = 0                                                              ------------( i )

According to Sridharacharya formula, we have:

                   x = (-b±$\sqrt{b^{2}-4ac}$) / 2a                                    ------------( ii )

                     when, ax²+bx+c = 0                                     ------------( iii )

From equation ( iii ), we get:

a = 4.9, b = 6 and c = -91.

Putting all the values in equation ( ii ), we get:

                x = (-6±$\sqrt{6^{2}-4*4.9*(-91) }$) / 2*4.9

By solving the above equation, we get:

                x = (-6±42.65) / 9.8                                           ------------( iv )

From equation ( iv ), we get two values of 'x', i.e.,

               x = (-6+42.65) / 9.8    or   x = (-6-42.65) / 9.8  

   ∴         x = 3.73                       or    x = -4.96