<span> x = -1 and x = -4.
you can use substitution
</span>
Answer:
3 oz
Step-by-step explanation:
Let x represent the number of oz. of the medal with 40% gold:
Set up an equation and solve for x:
0.4x + 7(0.9) = 0.75(x + 7)
0.4x + 6.3 = 0.75x + 5.25
6.3 = 0.35x + 5.25
1.05 = 0.35x
3 = x
So, you will need 3 oz. of the metal with 40% gold
