For a piecewise function to be continuous, the left-side and right-side limits must be equal to each other. Therefore, the left-side limit of f(x) is 8 because the derivative of 2x^2 is 4x, and then directly substituting x=2 gives us 4(2)=8. Therefore, the right-side limit must also equal 8. Therefore, k must be 6 because 2+6=8.
Yes because they both equal -15 because you actually turn -10+(-5) into a subtraction problem because if there's a + and -, you actually turn it into a minus and the answer is -15.