Question

Can someone pls answer these i will make them as brainiest

Answer 1

Answer:

Step-by-step explanation:

6) Let John's sister age be x

John's age = $\frac{1}{2}x+7$

$\frac{1}{2}x+7 = 35$      {Subtract 7 from both sides}

$\\\frac{1}{2}x=35-7\\\\\frac{1}{2}x=28\\\\x=28*2$

x = 56

His sister's age = 56 years

7) Longest side is hypotenuse. Use Pythagorean theorem.

hypotenuse² =base² + altituse²

15² = 12² + 9²

225 = 144 + 81

225 = 225

So, Pythagorean theorem  is satisfied. So, 15cm , 12 cm ,9 cm will make a right angled triangle.

9) q = -1

7p + 5q -3 = 0

7p + 5*(-1) - 3 = 0

    7p -5 - 3 = 0        {Combine like terms}

            7p - 8= 0              

                 7p = 8           {Divide both sides by 7}

                  p = 8/7

10) 8 - 3(x + 1) = 5 {Distributive property: a(b + c) = a*b + a*c}

     8 - 3x - 3 = 5          {Combine like terms}

          -3x + 5 = 5           {Subtract 5 from both sides}

               -3x = 5 - 5

              -3x = 0          

                x = 0

11)    -20x⁴  - 7x³  +  5x²   + 20 - ( 8x⁴  -7x²  + 29x - 17)

      = -20x⁴  - 7x³  +  5x² + 20 -  8x⁴  + 7x²  - 29x + 17

       = -20x⁴ - 8x⁴  - 7x³ + 5x² + 7x² - 29x + 20 + 17

      = -28x⁴ -7x³ + 12x² - 29x + 37