When asked to factor the x^2-121 a student gives the answer (x-11)(x-11) what is wron with this answer?

Given expression is x² - 121

This is called Difference of Squared terms, we have a formula that is given as :-

a² - b² = (a - b) · (a + b)

Now using the above formula in the given expression, we get :-

x² - 121

x² - (11)²

here a = x and b = 11

x² - (11)² = (x - 11) · (x + 11)

but it says that student gave the answer as (x - 11) · (x - 11).

So, student's answer should be (x - 11) · (x + 11) instead of product of two (x - 11) terms.

3. parallelogram

step-by-step explanation:

we turn each of our sides into direction vectors

ab=b-a=(3 - 7, 1 - 0) = (-4, 1)

bc=c-b=(1,6)

cd=d-c=(4,-1)

da=a-d=(-1,-6)

we see how the opposite sides have negated direction vectors; this is characteristic of a parallelogram.   we have congruent sides ab=cd and bc=da with unequal lengths because 1^2+6^2 is different from (-4)^2+1^2.   so it's not a square or a rhombus.  

we check the dot product of direction vectors of adjacent sides.   we have

ab dot bc = -4(1) + 1(6) = 2

that's not zero so the sides are not perpendicular.   we've ruled out rectangle.

the direction vectors indicate two pairs of congruent parallel sides, so we choose parallelogram over trapezoid.

pretty sure 750 each month!

step-by-step explanation: