Here’s a chart to help you.
If x + y = 5 and 3x = 2 then what you
do is:
3x = 2 and since you want the variable by itself you’d divide by 3... giving you an answer of x = 2/3 BUT YOURE NOT DONE YET
so now you plug what x equals (2/3) into the equation x + y = 5:
2/3 + y = 5
to solve this you have to subtract each side by 2/3 so x = 5 - 2/3
(5/1 - 2/3.... to get like denominators multiply the nominator and the denominator for 5/1 by 3 giving you: 15/3 - 2/3 = 13/3)
your final answer would be 13/3
For number 12 the answer is 15.36
Easy the first one message me if you need more help.
1 5
- + -
8 8
or
1/8 + 1.25/2