Question

Some for all values of x by factoring

Answer 1

Answer:

{-1, 10}

Step-by-step explanation:

Next time please share the entire set of instrutions.

x^2 - 9x - 15 = -5 should be rewritten in standard quadratic form:

x^2 - 9x - 10 = 0 = (x - 10)(x + 1) = 0.

Setting each factor equal to zero and then solving for x yields {-1, 10}

Answer 2

Answer:

{-1,10}

Step-by-step explanation:

$x^2-9x-15=-5$   given

$x^2-9x-10=0$   addition property of equality

$x^2+(x-10x)-10=x^2+x-10x-10=0$   x-10x = -9x

$x(x+1)-10(x+1)=0$   distributive property ( x( y + z ) = xy + xz

$(x-10)(x+1)=0$   distributive property (backwards)

$x-10=0;x=10;x+1=0;x=-1$   at least one factor of 0 has to be 0

{-1,10}