Question 397833
You can do this by completing the square.
{{{x^2 - 7x = -10}}}
{{{x^2 - 7x + (7/2)^2 = - 10 + (7/2)^2}}}
{{{x^2 - 7x + 49/4 = - 40/4 + 49/4}}}
Now both sides are a perfect square
{{{(x - 7/2)^2 = (3/2)^2}}}
Take the square root of both sides
(1) {{{x - 7/2 = 3/2}}}
and
(2) {{{x - 7/2 = -3/2}}}
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solving:
(1) {{{x = 7/2 + 3/2}}}
(1) {{{x = 5}}}
and
(2) {{{x - 7/2 = -3/2}}}
(2) {{{x = 7/2 - 3/2}}}
(2) {{{x = 2}}}
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Then 
{{{x - 5 = 0}}}
{{{x - 2 = 0}}}
therefore
{{{(x - 2)*(x - 5) = x^2 - 7x + 10}}}