How do you solve #x^2 - 10x + 21= 0# graphically?

2 Answers
G_Ozdilek
Jun 12, 2017

The graph is given below

Explanation:

Here it is graph{(x^2)-(10x)+21 [-3.705, 16.295, -5.055, 4.945]}

Note that at #x=5# you see it is the minimum

Jim G.
Jun 12, 2017

#x=3" or " x=7#

Explanation:

#"from the graph of " x^2-10x+21#
graph{x^2-10x+21 [-10, 10, -5, 5]}

#"the solution to "#

#x^2-10x+21=0" are the values of x where the"#
#"graph crosses the x-axis"#

#rArrx=3" or " x=7#

#color(blue)"As a check"#

#"Substitute these values into " x^2-10x+21#

#x=3to9-30+21=0larrcolor(red)" True"#

#x=7to49-70+21=0larrcolor(red)"True"#

Related questions
See all questions in Quadratic Functions and Their Graphs
Impact of this question
3368 views around the world
You can reuse this answer
Creative Commons License