Given: f(x)=0.7x^2+3.2x+1.5, find all roots to the nearest 0.001. what does find all roots mean in this instance?

Use the quadratic Equation: 
x = [ -b ±√ (b² - 4ac) ] / 2a 
x = [ -(3.2) ±√ ( (3.2)² - 4(.7)(1.5) ) ] / 2(.7) 
x = [ -3.2 ±√ ( (10.24 - 4.2 ) ] / 1.4 
x = [ -3.2 ±√6.04 ] / 1.4 
x = { [ -3.2 - √6.04 ] / 1.4, [ -3.2 +√6.04 ] / 1.4 } 
x = { -4.041, -0.530 }

Where is the diagram