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What two numbers add to 7 and multiply to -44

Sagot :

Answer:

The numbers are 11 and -4

Step-by-step explanation:

Given

Let the two numbers be [tex]x[/tex] and [tex]y[/tex]

such that:

[tex]x + y = 7[/tex]

[tex]x*y = -44[/tex]

Required

Find x and y

Make y the subject in: [tex]x + y = 7[/tex]

[tex]y = 7 - x[/tex]

Substitute [tex]y = 7 - x[/tex] in [tex]x*y = -44[/tex]

[tex]x(7-x) = -44[/tex]

Open bracket

[tex]-x^2 +7x = -44[/tex]

Rewrite as:

[tex]x^2 -7x -44=0[/tex]

Expand

[tex]x^2 +4x-11x -44=0[/tex]

Factorize

[tex]x(x +4)-11(x +4)=0[/tex]

Factor out x + 4

[tex](x -11)(x +4)=0[/tex]

Solve for x

[tex]x =11; x =-4[/tex]

Recall that:

[tex]y = 7 - x[/tex]

So:

[tex]y = 7-11 = -4[/tex]

or

[tex]y = 7--4 = 11[/tex]