Evaluate the following expression for x =2 and y = 4. 3x - 2y =
Evaluate means to solve so we need to think about what 3x and 2y mean. A number and a variable next to each other means to multiply so we are multiplying 3 times x and 2 times y. If x = 2 then we are multiplying 3 x 2 =6. If y=4 then we are multiplying 2 x 4 = 8. We then substitute our answers into the original problem making our new problem 6 -8 = -2.
1/2 divided by 3/5
When dividing fractions, I always use the phrase "Keep it, Change it, Flip it!" We keep 1/2, change the division to multiplication, and flip (use the reciprocal) of 3/5. The new problem reads 1/2 x 5/3. To multiply fractions you just multiply the two numerators together and then multiply the two denominators together. 1 x 5 =5 and 2 x 3 = 6, therefore the answer is 5/6.
3x + 7 < 5 Solve and graph the equation.
First, you need to isolate the variable. In order to do that, you need to get rid of everything that is on the same side of the equation as the variable. In this case it is the +7. We need to undo the +7, which means we need to subtract 7 from both sides to keep the equation balanced. We are left with 3x < -2. We then need to get rid of the 3. Since 3x shows multiplication, we need to divide by 3 on both sides to keep the equation balanced. Once we do that, we are left with x < -2/3. To graph this equation, we must use an open circle placed on -2/3. Because we read the equation x is less than -2/3, the arrow must be going in the left direction.