Solve 1/2 x + 3 <4x - 7
1 answer:
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Answer:
2x -y ≥ 4
Step-by-step explanation:
The intercepts of the boundary line are given, so it is convenient to start with the equation of that line in intercept form:
... x/(x-intercept) + y/(y-intercept) = 1
... x/2 + y/(-4) = 1
Multiplying by 4 gives the equation of the line.
... 2x -y = 4
This line divides the plane into two half-planes. The half-plane that is shaded is the one for larger values of x and/or smaller values of y than the ones on the line. So, for some given y, if we increase x we will get a number from our equation above that is greater than 4. Hence, the inequality we want is ...
... 2x -y ≥ 4
We use the ≥ symbol because the line is solid, so part of the solution space.
The topics you should learn are equating denominators and fractions. This is summing up simple fractions.
So we have to make denominators' numbers the same in order to sum up them all (we can sum fractions if the denominators are the same) , and we did it by cross product (that thing on the picture)
Equating by lcm (least common multiple) is the easiest way, because you might see bigger numbers on other questions, and cross product will bring much bigger numbers, so this technic might confuse you.
By the way lcm of 4 and 5 is already 20
Hope it helps!
