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Solve 2x2 – 5x 1 = 3 for x.

2 Answers

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2x^2-5x+1=3
2x^2= a -5x=b 1=c
the rule is: ax^2+bx+c= 0
therefore, we have to make the equation equals to zero:
2x^2-5x+1-3=0
2x^2-5x-2= 0
the rule here is: b^2-ac:
delta= 25-16=9
then you square the delta:
=√delta= 3
there are two ways to get x, either:
(-b-delta)÷2a
x...(1)= (5-3)÷4= 1/2
or, (b+delta)÷2a
x...(2)= (5+3)÷4= 2
hope it makes sense.

User Indimental
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7.1k points
4 votes

For this case we have the following polynomial:


image

Rewriting the polynomial we have:


image

Using the quadratic formula to find the solutions we have:


x = (-b+/-√(b^2 - 4ac))/(2a)

Substituting values:


x = (-(-5)+/-√((-5)^2 - 4(2)(-2)))/(2(2))

Rewriting:


x = (5+/-√(25+16))/(4)


x = (5+/-√(41))/(4)

Solution 1:


x = (5+√(41))/(4)

Solution 2:


x = (5-√(41))/(4)

User Royer Vazquez
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6.4k points