Datrys =(a+b)^2-(a-b)^2

$$= ( a + b ) ^ { 2 } - ( a - b ) ^ { 2 }$$

Enrhifo

$$4ab$$

Camau Ateb

Defnyddio'r theorem binomaidd \left(p+q\right)^{2}=p^{2}+2pq+q^{2} i ehangu'r \left(a+b\right)^{2}.

$$a^{2}+2ab+b^{2}-\left(a-b\right)^{2}$$

Defnyddio'r theorem binomaidd \left(p-q\right)^{2}=p^{2}-2pq+q^{2} i ehangu'r \left(a-b\right)^{2}.

$$a^{2}+2ab+b^{2}-\left(a^{2}-2ab+b^{2}\right)$$

I ddod o hyd i wrthwyneb a^{2}-2ab+b^{2}, dewch o hyd i wrthwyneb pob term.

$$a^{2}+2ab+b^{2}-a^{2}+2ab-b^{2}$$

Cyfuno a^{2} a -a^{2} i gael 0.

$$2ab+b^{2}+2ab-b^{2}$$

Cyfuno 2ab a 2ab i gael 4ab.

$$4ab+b^{2}-b^{2}$$

Cyfuno b^{2} a -b^{2} i gael 0.

$$4ab$$

Ehangu

$$4ab$$

Camau Ateb

Defnyddio'r theorem binomaidd \left(p+q\right)^{2}=p^{2}+2pq+q^{2} i ehangu'r \left(a+b\right)^{2}.

$$a^{2}+2ab+b^{2}-\left(a-b\right)^{2}$$

Defnyddio'r theorem binomaidd \left(p-q\right)^{2}=p^{2}-2pq+q^{2} i ehangu'r \left(a-b\right)^{2}.

$$a^{2}+2ab+b^{2}-\left(a^{2}-2ab+b^{2}\right)$$

I ddod o hyd i wrthwyneb a^{2}-2ab+b^{2}, dewch o hyd i wrthwyneb pob term.

$$a^{2}+2ab+b^{2}-a^{2}+2ab-b^{2}$$

Cyfuno a^{2} a -a^{2} i gael 0.

$$2ab+b^{2}+2ab-b^{2}$$

Cyfuno 2ab a 2ab i gael 4ab.

$$4ab+b^{2}-b^{2}$$

Cyfuno b^{2} a -b^{2} i gael 0.

$$4ab$$