Give answer to 1 d.p

Mathematics

1 answer:

KATRIN_1 [288]2 years ago

8 0

Answer:

AB ≈ 5.6 cm

Step-by-step explanation:

Using the cosine ratio in the right triangle

cos62° = $\frac{adjacent}{hypotenuse}$ = $\frac{AB}{BC}$ = $\frac{AB}{12}$ ( multiply both sides by 12 )

12 × cos62° = AB , then

AB ≈ 5.6 cm ( to 1 dec. place )

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Solve for w. -22w-5)+5w-5(w+4) Simplify your answer as much as possible.

Anna [14]

Answer: −22w−25

Step-by-step explanation: Distribute:

=−22w+−5+5w+(−5)(w)+(−5)(4)

=−22w+−5+5w+−5w+−20

Combine Like Terms:

=−22w+−5+5w+−5w+−20

=(−22w+5w+−5w)+(−5+−20)

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3 years ago

Solve The Equation <br> 4x×9y=7<br> 4x-9y=9

hoa [83]

Answer:

$\large\boxed{x=\dfrac{9}{8}-\dfrac{\sqrt{109}}{8},\ y=-\dfrac{1}{2}-\dfrac{\sqrt{109}}{18}}\\or\\\boxed{x=\dfrac{9}{8}+\dfrac{\sqrt{109}}{2},\ y=-\dfrac{1}{2}+\dfrac{\sqrt{109}}{18}}$

Step-by-step explanation:

$\left\{\begin{array}{ccc}4x\times9y=7&(1)\\4x-9y=9&(2)\end{array}\right\\\\(2)\\4x-9y=9\qquad\text{subtract}\ 4x\ \text{from both sides}\\-9y=-4x+9\qquad\text{change the signs}\\9y=4x-9\qquad\text{substitute it to (1)}\\\\4x(4x-9)=7\qquad\text{use the distributive property}\ a(b+c)=ab+ac\\(4x)(4x)+(4x)(-9)=7\\(4x)^2-36x=7\\(4x)^2-2(4x)(4.5)=7\qquad\text{add}\ 4.5^2\ \text{to both sides}\\(4x)^2-2(4x)(4.5)+4.5^2=7+4.5^2\qquad\text{use}\ (a-b)^2=a^2-2ab+b^2$

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