Let's use a for number of days when he shot 50 shots and b for number of days when he shot 100 shots.
We have:
a + b = 20
We also know that he shot total of 1250 shots:
50a + 100 b = 1250
We have two equations. We can solve them for a and b. Let's rearange first equation for a:
a= 20 - b
We insert this into second equation:
50 * (20 - b ) + 100b = 1250
1000 - 50b + 100b = 1250
50b = 250
b = 5
a = 20 - 5
a = 15
Mark shot 100 shots on 5 days.
Divide 5 by 89 and you get a=17.8
On all of them sorry but if i dont know wich one to do then....
Ok so the first step would be to distribute 3 into 3x and -6. So 3 times 3x would be 9x. 3 times -6 is -18.
the equation now is
18 = 9x - 18
Now you would have to do inverse operation
18 = 9x - 18
+18 +18
36 = 9x
Now you would divide 9x into 36 to isolate the variable
36 / 9x = 4
x = 4