This can be seen as the same as (x)(x + 5) + (-2)(x + 5). So you are just multiplying the first value in the first brackets with both the values in the second brackets. This is xx + x5 which equals x^2 + 5x. Then you do the same for the second value from the first brackets, this is -2*x + (-2)*5 which equals -2x - 10. So all together the answer is: x^2 + 3x - 10.
This can also be calculated using the 'smily face method'.