Solve the quadratic equation $7x^2+21x-28=0$

Step-by-step Solution

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Final answer to the problem

$x=1,\:x=-4$
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Step-by-step Solution

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  • Find the derivative using the definition
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To find the roots of a polynomial of the form $ax^2+bx+c$ we use the quadratic formula, where in this case $a=7$, $b=21$ and $c=-28$. Then substitute the values of the coefficients of the equation in the quadratic formula: $\displaystyle x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}$

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$x=\frac{-21\pm \sqrt{21^2-4\cdot 7\cdot -28}}{2\cdot 7}$

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Learn how to solve quadratic equations problems step by step online. Solve the quadratic equation 7x^2+21x+-28=0. To find the roots of a polynomial of the form ax^2+bx+c we use the quadratic formula, where in this case a=7, b=21 and c=-28. Then substitute the values of the coefficients of the equation in the quadratic formula: \displaystyle x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}. Simplifying. To obtain the two solutions, divide the equation in two equations, one when \pm is positive (+), and another when \pm is negative (-). Subtract the values 35 and -21.

Final answer to the problem

$x=1,\:x=-4$

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Function Plot

Plotting: $7x^2+21x-28$

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0
a
b
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f
g
m
n
u
v
w
x
y
z
.
(◻)
+
-
×
◻/◻
/
÷
2

e
π
ln
log
log
lim
d/dx
Dx
|◻|
θ
=
>
<
>=
<=
sin
cos
tan
cot
sec
csc

asin
acos
atan
acot
asec
acsc

sinh
cosh
tanh
coth
sech
csch

asinh
acosh
atanh
acoth
asech
acsch

How to improve your answer:

Main Topic: Quadratic Equations

The quadratic equations (or second degree equations) are those equations where the greatest exponent to which the unknown is raised is the exponent 2.

Used Formulas

See formulas (1)

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