Page 787 - Algebra 1

*5. Multiple Choice Which is a possible value for the discriminant of the equation (113) graphed?
A -5 B 0 C3 D5
*6. Model Draw the graph of a quadratic equation that has a discriminant (113) that is greater than zero.
*7. Generalize Describe the values of the discriminant that indicate two real
(113) solutions.
*8. Solve this system 2
_2
y = -x + 8
by graphing.
*9. Error Analysis Two students are solving the system of equations
y = -2x + 10
(112) by substitution. Which student is correct? Explain the error.
(112)
y = x2 + 3
y = -3x + 1
Student A
y = x2 + 3 y = -3x + 1 x2 + 3 = -3x + 1
x2 +3+3x-1=0 x2 +3x+2=0 (x + 2)(x + 1) = 0
So, x = -2, x = -1, and the solutions are (-2, 7) and (-1, 4).
Student B
y = x2 + 3 y = -3x + 1 x2 +3-3x+1=0
x2 -3x+4=0 no solution
10. Geometry For safety reasons, a guy wire must connect the top of a utility pole to
(112) the ground at a particular angle. The utility pole is located at the base of a hill
described by the equation y = -_x2 + 2x. The equation for the correct angle of 25
the wire is y = -x + 14. At what altitude on the hill should the ground stake be located? (Assume all dimensions are in feet.)
*11. In designing a necklace, a goldsmith places a gold wire on a workbench so that (112) the wire takes on the shape of a parabola described by the equation y = _x2 . The
2 goldsmith then lays a straight wire across the first so that the second follows the
equation y = _x + 6. Use a graphing calculator to determine the coordinates for the 6
points of intersection. Round answers to the nearest whole number.
772 Saxon Algebra 1