How do you use the quadratic formula to solve #3.8x^2=4.7x-2.1#?

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Answer 1 · 2017-09-29T12:26:29

See a solution process below:

First, rewrite the equation as:

#3.8x^2 - color(red)(4.7x) + color(blue)(2.1) = 4.7x - color(red)(4.7x) - 2.1 + color(blue)(2.1)#

#3.8x^2 - 4.7x + 2.1 = 0 - 0#

#3.8x^2 - 4.7x + 2.1 = 0#

Now, we can use the quadratic equation to solve this problem:

For #color(red)(a)x^2 + color(blue)(b)x + color(green)(c) = 0#, the values of #x# which are the solutions to the equation are given by:

#x = (-color(blue)(b) +- sqrt(color(blue)(b)^2 - (4color(red)(a)color(green)(c))))/(2 * color(red)(a))#

Substituting:

#color(red)(3.8)# for #color(red)(a)#

#color(blue)(-4.7)# for #color(blue)(b)#

#color(green)(2.1)# for #color(green)(c)# gives:

#x = (-color(blue)((-4.7)) +- sqrt(color(blue)((-4.7))^2 - (4 * color(red)(3.8) * color(green)(2.1))))/(2 * color(red)(3.8))#

#x = (4.7 +- sqrt(22.09 - 31.92))/7.6#

#x = (4.7 +- sqrt(-9.83))/7.6#