(-4;2)
Step-by-step explanation:
1. if y=1/2 x+4, then 2y=x+8; it is possible to re-write as x-2y+8=0;
2. if x+4y=4, it is possible to re-write it as x+4y-4=0;
3. if x-2y+8=0 and x+4y-4=0, then x-2y+8=x+4y-4; β -2y+8=4y-4; β 6y=12; β y=2.
4. if y=2, then it is possible to substitute its value into any equation given in the condition:
x+4y=4 (substitution y=2); β x+8=4; β x= -4.
5. finally x= -4; y=2. It means (-4;2)
PS. the suggested solution is not the only way to resolve this task.
5 sweat shirts- $100
8 sweat shirts- $160
9 sweat shirts- $180
12 sweat shirts- $240
Step-by-step explanation:
Each sweat shirt costs $20