Question

Which equation shows the quadratic formula used correctly to solve 5x2 + 3x – 4 = 0 for x?

Answer 1

Answer:

$x=\frac{-3\pm\sqrt{(3)^2-4(5)(-4)}}{2(5)}$

Therefore, Option 1 is correct.

Step-by-step explanation:

We have been given the quadratic equation:

$5x^2+3x-4=0$

If we compare it will general quadratic equation which is: $ax^2+bx+c=0$

Here, a=5,b=3 and c= -4.

Now, we will use the formula:

And then $x=\frac{-b\pm\sqrt{D}}{2a}$

Where,$D=b^2-4ac$

$x=\frac{-3\pm\sqrt{(3)^2-4(5)(-4)}}{2(5)}$

Therefore, Option 1 is correct.

Answer 2

Answer:

Choice a is correct answer.

Step-by-step explanation:

Given equation is :

5x²+3x-4 = 0

we have to solve it by finding the value of x.

ax²+bx+c = 0 is general quadratic equation.

x = ( -b±√b²-4ac) / 2a is quadratic formula which is used to find the value of x in quadratic equation.

Comparing given equation with quadratic equation , we get

a = 5 , b = 3 and c = -4

putting above values in quadratic formula  , we get

x = ( -(3)±√(3)²-4(5)(-4) ) / 2(5)

x = ( -3±√(3)²-4(5)(-4) / 2(5) which is the answer.