That would happen when the factors have opposite signs.
Answer:
The point (0,4) doesn't make either equation true.
Step-by-step explanation:
Consider the equations.
and 
We need to determine the point (0,4) make either equation true.
Substitute x=0 and y=4 in
Which is false.
Substitute x=0 and y=4 in 


Which is false.
Hence, the point (0,4) doesn't make either equation true.
The baker needs to use 100/3 pounds of 90% chocolate to make the cake.
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Equation </h3>
An equation is an expression used to show the relationship between two or more numbers and variables.
Let x represent the amount of 90% chocolate. Using equation:
100 * 70% + x * 90% = (x + 100) * 75%
100 * 0.7 + 0.9 * x = (x + 100) * 0.75
70 + 0.9x = 0.75x + 75
x = 100/3
The baker needs to use 100/3 pounds of 90% chocolate to make the cake.
Find out more on Equation at: brainly.com/question/22688504