8.8.5 Æfing

8.8.5 • Æfing

Ljúktu við eftirfarandi spurningar til að æfa færnina sem þú hefur lært í þessari kennslustund.

Hver eftirfarandi stæðna er jafngild þessari stæðu?

1. $$(10+12)(10-12)$$
2. $${(10-12)}^2$$
3. $$(10-12)(10-12)$$
4. $$(10+12)(10+12)$$

   Fyrir spurningar 2–10 skaltu velja stæðuna á þáttuðu formi.

   2.

   $$c^2-25$$

1. $$(c+5)(c+5)$$
2. $$(c-5)(c+5)$$
3. $$(c-5)(c-5)$$
4. $$c(c-25)$$

   3.

   $$9w^2-121$$

1. $$(3w-11)(3w-11)$$
2. $$w(9w-121)$$
3. $$(3w+11)(3w+11)$$
4. $$(3w-11)(3w+11)$$

   4.

   $$h^2-121$$

1. $$(h+11)(h+11)$$
2. $$(h-11)(h-11)$$
3. $$(h-11)(h+11)$$
4. $${(h-11)}^2$$

   5.

   $$64-d^2$$

1. $$(8+d)(8+d)$$
2. $$(8-d)(8+d)$$
3. $$(8-d)(8-d)$$

4. Ekki hægt

   6.

   $$4b^2-25$$

1. $$(2b+5)(2b+5)$$
2. $$b(4b-25)$$
3. $$(2b-5)(2b-5)$$
4. $$(2b-5)(2b+5)$$

   7.

   $$49-81z^2$$

1. $$(7-9z)(7+9z)$$
2. $$z(49-81z)$$
3. $$(7-9z)(7-9z)$$
4. $$(7+9z)(7+9z)$$

   8.

   $$100y^2-4$$

1. $$(10y-2)(10y-2)$$
2. $$(10y-2)(10y+2)$$
3. $$(10y+2)(10y+2)$$

4. Ekki hægt

   9.

   $$x^2+9$$

1. $$(x+3)(x+3)$$
2. $$(x-3)(x+3)$$
3. $$(x-3)(x-3)$$

4. Ekki hægt

   10.

   $$144-16g^2$$

1. $$(12-4g)(12-4g)$$
2. $$(12+4g)(12+4g)$$
3. $$(12-4g)(12+4g)$$

4. Ekki hægt