Please help with math ?

Question

1.8x+6y forx=9 and y=5?

2.14a-5b for a=7 and b=9

Answer 1

substitute x=9 in the equation and y=5

1.8*9+6*5=46.2

2.14*7-5*9= -30.02

Answer 2

8(9)+6(5)=102

2. 14(7)-5(9)=46

Answer 3

1.

8*9 + 6*5 = 72 + 30 = 102

2.

14*7 - 5*9 = 98 - 45 = 53

Answer 4

These problems are very easy if you know how to do them.  The trick is to simply place the number in for where you see the variable.

8x + 6y    x=9 and y=5

So wherever you see an x you put a 9 and the same for y

8*9 + 6*5 =

72 + 30 =

102

Now do the same for 14a - 5b   a=7 and b=9

So wherever you see an a put a 7 and a b put a 9

14*7 - 5*9 =

98 - 45 =

53

Hope this helped