Question

x×a+x×b-50. x=5. a+b=13

Answer 1

x= 5
a+b= 13

xa+xb-50=
x(a+b)-50=
5•13-50=
65-50= 15

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Answer 2

x·a + x·b - 50 =  

= x·(a + b) - 50

= 5•13 - 50

= 65 - 50

= 15