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messersmith_power_intermediate_algebra_1e_ch4_7_10

Sometimes an x-intercept is not an integer. Solve 2x2 x 15 0 using a graphing calculator. Enter 2x2 x 15 into the calculator, and press GRAPH. The x-intercept on the right side of the graph is between two tick marks, so it is not an integer. To fi nd the x-intercept, press 2nd TRACE and select 2:zero. Move the cursor to the left of one of the intercepts and press ENTER, then move the cursor again, so that it is to the right of the same intercept and press ENTER. Press ENTER one more time, and the calculator will reveal the intercept and, therefore one solution to the equation. Press 2nd MODE to return to the home screen. Press X,T,,n MATH ENTER ENTER to display the x-intercept in fraction form: x 5 2 . Since the other x-intercept appears to be 3, press TRACE 3 ENTER to reveal that x 3 and y 0. Solve using a graphing calculator. 1) x2 3x 4 0 2) 2x2 5x 3 0 3) x2 5x 14 0 4) 3x2 17x 10 0 5) x2 7x 12 0 6) 2x2 9x 10 0 ANSWERS TO YOU TRY EXERCISES 1) a) {0, 9} b) e 2 5 , 7 f 2) 56, 36 3) a) 55, 16 b) e 4 5 , 5 f c) 57, 36 d) {0, 8} e) e2, 4 3 f 4) a) e10, 7 2 , 1 f b) 50, 5, 56 ANSWERS TO TECHNOLOGY EXERCISES 1) {1, 4} 2) e 1 2 , 3 f 3) {7, 2} 4) e 2 3 , 5 f 5) {4, 3} 6) e 2, 5 2 f 7.4 Exercises Do the exercises, and check your work. Objective 1: Solve a Quadratic Equation of the Form ab 0 1) Explain the zero product rule. 2) When Ivan solves c(c 7) 0, he gets a solution set of {7}. Is this correct? Why or why not? Solve each equation. 3) (m 9)(m 8) 0 4) (a 10)(a 4) 0 5) (q 4)(q 7) 0 6) (x 5)(x 2) 0 www.mhhe.com/messersmith SECTION 7.4 Solving Quadratic Equations by Factoring 399


messersmith_power_intermediate_algebra_1e_ch4_7_10
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