Question

-2(7-5х)(2х+3)0

Answer 1

-2(7-5х)(2х+3)≥0

-2(-10х^2+21-х)≥0 |:2

10х^2+х-42 ≥0

D^2=1^2-4*10*(-42)=1681

D=41

x1=(-1-41)/2*10=-2,1

x2=(-1+41)/20=2

ответ: [2;+бесконечности]

Answer 2

It looks like you want to simplify the expression: -2(7 - 5x)(2x + 3). To do this, you can use the distributive property (also known as the FOIL method for binomials). Here's how you can do it step by step:

1. Start by distributing -2 to both terms inside the first set of parentheses: -2 * 7 = -14 -2 * (-5x) = 10x

So far, the expression simplifies to: -14 + 10x.

2. Now, distribute -2 to both terms inside the second set of parentheses: -2 * 2x = -4x -2 * 3 = -6

So the second part of the expression simplifies to: -4x - 6.

3. Now, you can combine the results from steps 1 and 2: (-14 + 10x) * (-4x - 6)

4. Apply the distributive property (FOIL) to multiply the two binomials: (-14) * (-4x) + (-14) * (-6) + (10x) * (-4x) + (10x) * (-6)

5. Simplify each term: 56x + 84 - 40x^2 - 60x

6. Combine like terms: -40x^2 + (56x - 60x) + 84

7. Further simplify the x terms inside the parentheses: -40x^2 - 4x + 84

So, the simplified expression is: -40x^2 - 4x + 84.