Find the product of the two binomials

An easy way to approach this is through the FOIL (firsts, outsides, insides, lasts) method. First you find the product of the first two terms in the parentheses (3x and 2x), then the outside terms (3x and -3), inside terms (4 and 2x), followed by the last terms in the parentheses (4 and -3).
So, 3x times 2x = 6x2, 3x times -3 = -9x, 4 times 2x = 8x, 4 times -3 = -12
The product becomes 6x2 - 9x + 8x - 12. Combining like terms with addition/subraction, it becomes 6x2 - x - 12

The same method may be used for (x+5)2, which can be expanded to (x+5)(x+5).
So, the product of the firsts = x2,  the outside product = 5x,  the inside product = 5x, and the product of the lasts = 25
The like terms can be combined here as well, to give x2 + 10x + 25
This FOIL method might be tricky at first but after the first few times it becomes really handy
Hope this helps