1. ## evaluation

when $c=-7$and $d=4$

$\sqrt{d} - dc^2$

$\sqrt{4} - 4 x (-7)^2$

$2 - 4 x (-7)^2 = -194$

this right?

when $c=-7$and $d=4$

$\sqrt{d} - dc^2$

$\sqrt{4} - 4 x (-7)^2$

$2 - 4 x (-7)^2 = -194$

this right?
it is right but $\sqrt{4}=\mp 2$ since $2^2=4$ and $(-2)^2=4$ so you will have two answers the first one you find it
the second one

$-2-4(-7)^2=-198$

3. So are you saying there are two answers?

So are you saying there are two answers?
yeah

5. Ok so i'm not sure what to do now then?

Ok so i'm not sure what to do now then?
did you know that

$(-2)^2=4$
$(-4)^2=16$
$(-7)^2=49$

so

$\sqrt{4}=\mp 2$
$\sqrt{16}=\mp 4$
$\sqrt{49}=\mp 7$

in general
$\sqrt{a^2}=\mp a$ a is real number

in you question

$\sqrt{4}-4(-7)^2$ have two solutions since $\sqrt{4}=2$ and $\sqrt{4}=-2$

first one
$2-4(49)=2-196=-194$

second one

$-2-4(49)=-2-196=-198$

7. Does the same apply to this formula

$a = -7, b = 4$

$a - b(a + b)$

$(-7) - 4((-7)+4) = 5$

Does the same apply to this formula

$a = -7, b = 4$

$a - b(a + b)$

$(-7) - 4((-7)+4) = 5$
it is correct

So are you saying there are two answers?
One might say that the evaluation has two answers, but this would be incorrect.

While one solves "x^2 = 4" for the two solution values, -2 and +2, "the" value of the square root of 4, sqrt[4], is defined to be the principal (that is, the positive real) value: sqrt[4] = 2.

So no, there will most definitely not be two answers to this one evaluation exercise!

$\sqrt{d}\, -\, dc^2\, =\,\sqrt{4}\, -\, (4)(-7)^2$

. . . $=\, 2\, -\,4(49)\, =\, 2\, -\, 196\, =\, -194$

And the above is the only answer!