4x^2+28x=-49
First put into standard form:
4x^2 + 28x + 49 = 0
Then 'plug into' the quadratic equation
a=4 b=28 c=49
(-28 +- sqrt( (28)(28) -4(4)(49) ) )/2(4)
(-28+- 0)/8
-28/8 = 3 1/2 You can substitute 3.5 into the equation to be sure it is correct.
