To plot a quadratic graph you need the y intercept, the X intercepts(the roots) and the minimum/ maximum.
For the first question:
Y intercepts is -7, so u have the point(0,-7)
U can complete the square for the max/min
-x2-4x-7=y
-1(x2+4x)-7=y
-1((X+2)2-4)-7=y
-1(X+2)2+4-7=y
-1(X+2)2-3=y
It's a negative quadratic so it's a maximum
U need to make the number in the bracket = 0, so when X =-2, y = -3
So maximum point is (-2,-3)
To find the roots u make the equation equal to 0 and find what X equals. U can do this using quadratic formula, factorising or completing the square. -1(X+2)2-3=0 -1(X+2)2=3 (X+2)2= -3 X+2= √-3 You can't square root a negative number so there are no roots, meaning the line will not touch the X axis.
Now u just need to plot the y int and maximum on ur graph The graph