Question

Which equations are true for x = –2 and x = 2? Select two options x2 – 4 = 0 x2 = –4 3x2 + 12 = 0 4x2 = 16 2(x – 2)2 = 0

Answer 1

Here we try the method of trial and error to find out if the equations have a common answer as zero

Explanation:

Now,

(a) x²-4=0

(b) x²=-4

(c) 3x²+12=0

(d) 4x²=16

(e) 2(x-2)2=0

Here if we check the first equation i.e x²-4=0

Equating - 2²-4=4-4

=0

2²-4= 4-4

=0

So option (a) is true

Now x²=-4

Substituting, - 2²=4 & 2²=4

So here we get 4≠-4

Therefore, (b) is not true

Now 3x²+12=0

3(-2)²+12= 3(4)+12

=12+12= 24

3(2)²+12= 12+12

= 24

4x²=16

Substituting, 4(-2)²= 4(4)= 16

4(2)²= 4(4)= 16

So option (d) is also true

Now, 2(x-2)2=0

Substituting, 2(-2-2)2= 2(-4)2

4(-4)= - 16

2(2-2)2= 2(0)2

=4(0)=0

Here when we put x=-2, we get - 16

when we put x=2, we get 0

So the following equation is true only for x=2 and not x=-2

I hope this helps ;)