9x - y = 15
2x + 8y = 28
Use the substitution method.
Solve for y in the first equation.
9x - y = 15
-y = 15 - 9x
y = -15 + 9x
Now plug in y into the second equation.
2x + 8(-15 + 9x) = 28
2x - 120 + 72x = 28
74x - 120 = 28
74x = 148
x = 2
Plug x back into the rewritten first equation.
y = -15 + 9(2)
y = -15 + 18
y = 3
x = 2, y = 3
Answer:
a) 7 weeks b) George's
Step-by-step explanation:
Sally's score can be modeled by 10x+850.
George's score can be modeled by 50x+570.
We can set them equal to each other to see when they intersect.
10x+850=50x+570
40x=280
x=7
If George overtakes her in the 7th week, of course he'll have the higher score in 12 weeks.
6x+18y+12z
Hope this helps!
490 divided by 35 equals 14. It would take Jack 14 minutes to write a 490 word essay.
