4.9t^2-2.78t-1.15=0 what is the value of T

t = 139/490 + sqrt (75671) / 490 or t = 139/490 - sqrt (75671) / 490

Step-by-step explanation:

Solve for t:

4.9 t^2 - 2.78 t - 1.15 = 0

4.9 t^2 - 2.78 t - 1.15 = (49 t^2) / 10 - (139 t) / 50 - 23/20:

(49 t^2) / 10 - (139 t) / 50 - 23/20 = 0

Multiply both sides by 10/49:

t^2 - (139 t) / 245 - 23/98 = 0

Add 23/98 to both sides:

t^2 - (139 t) / 245 = 23/98

Add 19321/240100 to both sides:

t^2 - (139 t) / 245 + 19321/240100 = 75671/240100

Write the left hand side as a square:

(t - 139/490) ^2 = 75671/240100

Take the square root of both sides:

t - 139/490 = sqrt (75671) / 490 or t - 139/490 = - sqrt (75671) / 490

Add 139/490 to both sides:

t = 139/490 + sqrt (75671) / 490 or t - 139/490 = - sqrt (75671) / 490

Add 139/490 to both sides:

Answer: t = 139/490 + sqrt (75671) / 490 or t = 139/490 - sqrt (75671) / 490