Can anyone help me with this please? I need help along with an explanation.

a + b = 7

Step-by-step explanation:

a^2 - b^2 = 21

Factor the left side. It is the difference of two squares which factors into the product of a sum and a difference.

(a + b)(a - b) = 21

We are told a - b = 3, so substitute 3 for the factor a - b.

(a + b)(3) = 21

Divide both sides by 3.

a + b = 7

1 x=22.52

2: 65/39=604+39x

65x-39x=604

26x=604

x=604/26

×=23.23