It would help a lot if you would translate all the words; but it looks like it lists values of [imath]y_i[/imath], and then tells you that [imath]x_i=i[/imath], meaning that [imath]x_1=1,x_2=2,x_3=3,x_4=4[/imath]. (It mentions X, but I don't know what it says about that.)
Then they have just carried out the various sums. For example, [math]\sum_{i=1}^4(x_i+y_i)=(x_1+y_1)+(x_2+y_2)+(x_3+y_3)+(x_4+y_4)=(1+4)+(2+7)+(3+2)+(4+1)=5+9+5+5=24[/math]
I see nothing to solve here! It's all been done. But presumably you are expected to confirm their calculations.
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