Question

Y= -10x - 9
7x + 5y = -217​

Answer 1

7x + 5(-10x - 9) = -217

7x - 50x - 45 = -217

-43x - 45 = -217

-43x = -172

x = 4

y = -10(4) - 9

y= -40 - 9

y= -49

(4, -49)

Answer 2

`x=4,\:y=-49`

Explanation:

we are given with two linear equations and asked to solve them for x and y .

We will solve them by substitution method.

Given that

`y=-10x-9`

We replace this value of y in second equation that is

`7x+5y=-217`

`\mathrm{Subsititute\:}y=-10x-9`

`7x+5\left(-10x-9\right)=-217`

`7x-50x-45=-217`

`\mathrm{Add\:similar\:elements:}\:7x-50x=-43x`

`-43x-45=-217`

`\mathrm{Add\:}45\mathrm{\:to\:both\:sides}`

`-43x=-172`

`\mathrm{Divide\:both\:sides\:by\:}-43`

`x=4`

`\mathrm{For\:}y=-10x-9`

`\mathrm{Subsititute\:}x=4`

`y=-10\cdot \:4-9`

`y=-49`

`\mathrm{The\:solutions\:to\:the\:system\:of\:equations\:are:}`

`x=4,\:y=-49`