Question

Given that a = 10,

b = 2x + 5, and
ab = 6x² +11x-10, find x.

A. 8/10
B. 7/2
C. 4
D. 6

Answer 1

4

Explanation:

used the calculator and plugged it in while taking the test. this is correct

Answer 2

Since
`a = 10` and
`b = 2x + 5`, we have

`ab=10(2x+5)=20x+50`

So, the equation becomes

`ab = 6x^2 +11x-10 \iff 20x+50= 6x^2 +11x-10 \iff 6x^2-9x-60=0`

The solutions to this equation are 4 and -5/2, so I'm afraid there's a typo in your question.