Solve this equation and pick the correct answer

2x^2+5x-7=0

1. x = 7 and x = -2

2. x = -7/2 and x = 1

3. x = -7 and x = 2

4. x = 7/2 and x = -1

I have summer homework and I do not understand this question an anyone explain it to me. Thanks!

Respuesta :

Answer:

2.  x = -7/2 and x = 1.

Step-by-step explanation:

2x^2 + 5x - 7 = 0

(2x + 7)(x - 1) = 0

x = -7/2, 1.

Answer:

The answer is 2) x = -7/2 and x = 1

Step-by-step explanation:

You have to use the a•c method.

a^2+b+c

a = 2

b = 5

c = -7

Multiply a(b) = 2(-7)

That'll equal -14. Then find factors of -14 that, when added, will equal to 5 (which is the 'b').

The factors are 7, -2.

Break up the 5x in the equation to -2x and 7x.

It looks like this: 2x^2-2x+7x-7=0

Then group them into two separate groups with parentheses.

It looks like this: (2x^2-2x) + (7x-7)

Then take out the GCF (Greatest Common Factor) for each of the groups.

Like this: 2x(x-1) + 7(x-1)

Then group the 2x and 7 together and only use one of the (x-1).

Like this: (2x+7)(x-1)

Then solve each parentheses by making both equal to zero separately.

Like this: 2x+7 = 0, x-1 = 0

Then solve each one of them for x.

2x+7 = 0

-7 -7

2x = -7

2x/2 = -7/2

x = -7/2

x-1 = 0

+1 +1

x = 1

Then you have your answers: x = -7/2 and x = 1