One solution of 21x^2 + bx -4 = 0 is -4/3. find b and the other solution.

see explanation

Step-by-step explanation:

Given that x = - is a solution of the equation, then

Substitute this value into the equation and solve for b

21 (- )² + b (- ) - 4 = 0

21 × - b - 4 = 0

- b - 4 = 0

Multiply through by 3

112 - 4b - 12 = 0

100 - 4b = 0 ( subtract 100 from both sides )

- 4b = - 100 ( divide both sides by - 4 )

b = 25 ← value of b

The equation can now be written as

21x² + 25x - 4 = 0 ← in standard form

with a = 21, b = 25, c = - 4

Use the quadratic formula to solve for x

x = ( - 25 ± ) / 42

  = ( - 25 ± ) / 42

  = ( - 25 ± 31 ) / 42

x = = = -

or x = =   =

The other solution is x =

step-by-step explanation:

nope.   happens to me as well.

-aparri